birthday traffic

How did birthdays in France change between 1968–1977 and 2014–2023?

Published by Birthday Traffic · · Sources and method

Inside one series, INSEE’s daily births for metropolitan France from 1968 to 2023, each date’s share of its own year’s births can be averaged over 1968–1977 and over 2014–2023 and compared. The largest change is seasonal: the busiest month per day was May in the first window and July in the second, so spring dates fell and autumn dates rose almost across the board. May 8 fell the most (−19.9%) and October 26 rose the most (+13.5%). The weekend gap opened and then narrowed: a Saturday or Sunday recorded 97% of a weekday’s births in 1968, 76% in 1995 and 85% in 2023. The series records counts.

How the comparison is built

A share removes the change in annual birth totals: it is the date’s births divided by that year’s births, in parts per 100,000, averaged across the ten years of each window. Both windows are inside the same file. Every table counts the Saturdays and Sundays each date fell on in each window, because in this series a weekend day records fewer births and a date that fell on more weekend days in one window looks quieter there whatever else happened. Over ten years a fixed date falls on a weekend about three times, so the weekend column moves a date by a few percent at most; the moves at the top of the tables are larger than that.

The season moved

Births per day by month, metropolitan France, 1968–1977 and 2014–2023, index (100 = the window’s average day)

Twelve months, each window indexed to its own average day, the first window in blue and the second in rose.

Births per day by month, metropolitan France, 1968–1977 and 2014–2023, index (100 = the window’s average day)Twelve months, each window indexed to its own average day, the first window in blue and the second in rose.9095100105110115JanFebMarAprMayJunJulAugSepOctNovDec1968–1977, Jan: 97.81968–1977, Feb: 99.61968–1977, Mar: 102.51968–1977, Apr: 106.11968–1977, May: 108.91968–1977, Jun: 104.91968–1977, Jul: 102.91968–1977, Aug: 97.01968–1977, Sep: 97.71968–1977, Oct: 94.41968–1977, Nov: 93.21968–1977, Dec: 95.02014–2023, Jan: 97.72014–2023, Feb: 97.62014–2023, Mar: 95.52014–2023, Apr: 95.32014–2023, May: 99.12014–2023, Jun: 101.82014–2023, Jul: 105.02014–2023, Aug: 103.22014–2023, Sep: 103.92014–2023, Oct: 102.62014–2023, Nov: 100.22014–2023, Dec: 97.92014–20231968–1977
1968–19772014–2023May led in 1968–1977; July leads in 2014–2023. Each series is indexed to its own window, so the lines show shape.
Births per day by month, indexed to each window’s average day
Month1968–19772014–2023Change in index
January97.897.7−0.1
February99.697.6−2.1
March102.595.5−7.0
April106.195.3−10.8
May108.999.1−9.8
June104.9101.8−3.1
July102.9105.0+2.2
August97.0103.2+6.2
September97.7103.9+6.2
October94.4102.6+8.2
November93.2100.2+7.0
December95.097.9+2.8

Dates whose share fell most

Ten largest falls: share per 100,000, 1968–1977 to 2014–2023

One line per date from its early-window share to its late-window share.

Ten largest falls: share per 100,000, 1968–1977 to 2014–2023One line per date from its early-window share to its late-window share.220240260280300320May 8: 304.2 → 243.71968–1977: 304.22014–2023: 243.7May 8−19.9%May 1: 286.3 → 239.11968–1977: 286.32014–2023: 239.1May 1−16.5%April 22: 298.9 → 255.51968–1977: 298.92014–2023: 255.5April 22−14.5%May 14: 307.1 → 263.71968–1977: 307.12014–2023: 263.7May 14−14.1%April 17: 294.9 → 254.21968–1977: 294.92014–2023: 254.2April 17−13.8%May 2: 302.3 → 262.51968–1977: 302.32014–2023: 262.5May 2−13.2%April 29: 301.4 → 262.11968–1977: 301.42014–2023: 262.1April 29−13.1%April 2: 287.2 → 250.91968–1977: 287.22014–2023: 250.9April 2−12.6%May 21: 302.2 → 264.01968–1977: 302.22014–2023: 264.0May 21−12.6%April 23: 294.0 → 258.21968–1977: 294.02014–2023: 258.2April 23−12.2%
1968–19772014–2023, fell
Largest falls in share of births in metropolitan France per 100,000, 1968–1977 to 2014–2023
Date1968–19772014–2023ChangeWeekend days 68–77Weekend days 14–23
May 8304.2243.7−19.9%3 of 103 of 10
May 1286.3239.1−16.5%3 of 103 of 10
April 22298.9255.5−14.5%2 of 103 of 10
May 14307.1263.7−14.1%2 of 104 of 10
April 17294.9254.2−13.8%3 of 103 of 10
May 2302.3262.5−13.2%3 of 103 of 10
April 29301.4262.1−13.1%2 of 103 of 10
April 2287.2250.9−12.6%2 of 104 of 10
May 21302.2264.0−12.6%2 of 104 of 10
April 23294.0258.2−12.2%2 of 104 of 10

May 1 and May 8 are fixed public holidays in France; the series records how many births fell on each date in each window.

Dates whose share rose most

Ten largest rises: share per 100,000, 1968–1977 to 2014–2023

One line per date from its early-window share to its late-window share.

Ten largest rises: share per 100,000, 1968–1977 to 2014–2023One line per date from its early-window share to its late-window share.240250260270280290300October 26: 251.3 → 285.21968–1977: 251.32014–2023: 285.2October 26+13.5%October 20: 254.8 → 287.41968–1977: 254.82014–2023: 287.4October 20+12.8%November 10: 256.1 → 288.91968–1977: 256.12014–2023: 288.9November 10+12.8%November 3: 253.9 → 286.31968–1977: 253.92014–2023: 286.3November 3+12.8%October 12: 256.3 → 287.11968–1977: 256.32014–2023: 287.1October 12+12.0%October 17: 252.2 → 281.81968–1977: 252.22014–2023: 281.8October 17+11.8%October 19: 253.0 → 281.41968–1977: 253.02014–2023: 281.4October 19+11.2%November 6: 252.6 → 280.61968–1977: 252.62014–2023: 280.6November 6+11.1%November 9: 255.6 → 283.71968–1977: 255.62014–2023: 283.7November 9+11.0%November 7: 254.5 → 281.71968–1977: 254.52014–2023: 281.7November 7+10.7%
1968–19772014–2023, rose
Largest rises in share of births in metropolitan France per 100,000, 1968–1977 to 2014–2023
Date1968–19772014–2023ChangeWeekend days 68–77Weekend days 14–23
October 26251.3285.2+13.5%4 of 102 of 10
October 20254.8287.4+12.8%3 of 102 of 10
November 10256.1288.9+12.8%3 of 102 of 10
November 3253.9286.3+12.8%3 of 102 of 10
October 12256.3287.1+12.0%4 of 102 of 10
October 17252.2281.8+11.8%3 of 103 of 10
October 19253.0281.4+11.2%4 of 102 of 10
November 6252.6280.6+11.1%3 of 103 of 10
November 9255.6283.7+11.0%4 of 102 of 10
November 7254.5281.7+10.7%3 of 103 of 10

The weekend gap, 1968–2023

Saturday and Sunday births per day as a percentage of Monday-to-Friday births per day in the same year. It fell from 97% in 1968 to a low of 76% in 1995, then rose to 85% in 2023. Each year is measured against itself.

Weekend births as a percentage of weekday births, metropolitan France, 1968–2023

Saturday and Sunday births per day against Monday-to-Friday births per day in the same year, one point per year.

Weekend births as a percentage of weekday births, metropolitan France, 1968–2023Saturday and Sunday births per day against Monday-to-Friday births per day in the same year, one point per year.708090100196819731978198319881993199820032008201320182023weekend level, 1968: 96.6%weekend level, 1969: 95.8%weekend level, 1970: 95.6%weekend level, 1971: 95.6%weekend level, 1972: 95.7%weekend level, 1973: 94.2%weekend level, 1974: 94.9%weekend level, 1975: 93.8%weekend level, 1976: 93.7%weekend level, 1977: 92.2%weekend level, 1978: 91.7%weekend level, 1979: 91.0%weekend level, 1980: 90.7%weekend level, 1981: 89.1%weekend level, 1982: 87.6%weekend level, 1983: 87.6%weekend level, 1984: 86.6%weekend level, 1985: 85.6%weekend level, 1986: 84.3%weekend level, 1987: 83.2%weekend level, 1988: 82.5%weekend level, 1989: 80.6%weekend level, 1990: 80.5%weekend level, 1991: 79.0%weekend level, 1992: 78.2%weekend level, 1993: 76.8%weekend level, 1994: 76.0%weekend level, 1995: 75.5%weekend level, 1996: 77.0%weekend level, 1997: 76.1%weekend level, 1998: 76.5%weekend level, 1999: 77.0%weekend level, 2000: 77.6%weekend level, 2001: 77.4%weekend level, 2002: 77.1%weekend level, 2003: 77.8%weekend level, 2004: 78.4%weekend level, 2005: 78.3%weekend level, 2006: 79.0%weekend level, 2007: 79.9%weekend level, 2008: 80.8%weekend level, 2009: 80.7%weekend level, 2010: 81.5%weekend level, 2011: 81.4%weekend level, 2012: 82.3%weekend level, 2013: 83.2%weekend level, 2014: 83.4%weekend level, 2015: 83.8%weekend level, 2016: 84.4%weekend level, 2017: 84.0%weekend level, 2018: 85.1%weekend level, 2019: 85.5%weekend level, 2020: 85.0%weekend level, 2021: 84.7%weekend level, 2022: 84.6%weekend level, 2023: 85.0%weekend level
The low point is 1995; the line has climbed since.
Weekend level by year, metropolitan France, every fifth year and the last
YearWeekend births per day, % of weekday
196896.6%
197394.2%
197891.7%
198387.6%
198882.5%
199376.8%
199876.5%
200377.8%
200880.8%
201383.2%
201885.1%
202385.0%

Did the calendar get flatter?

Across the 365 dates that occur every year, the standard deviation of the per-date share was 14.46 per 100,000 in 1968–1977 and 11.48 in 2014–2023; the busiest date stood 1.33 times above the quietest then and 1.40 times later. By standard deviation the calendar is flatter in the later window; by the gap between its two extremes it is slightly lumpier. The two measures answer different questions and are both given. February 29 occurred 3 times in the first window and 2 in the second and is kept out of these figures.

Check how rare your own birthday is → · France’s ranking, 2004–2023 · The same comparison for the U.S. · And for England & Wales

Sources, method and limits

Source: INSEE, T79jnais, daily births in metropolitan France, 1968–2023, open licence of the publisher; 20,454 daily rows and 42,899,901 births, metropolitan France, a series separate from the whole-of-France detail file. Shares are per 100,000 of each year’s births; window means are simple means of the ten annual shares; weekend counts come from the calendar date of each row.

Public holidays, the weekday each date fell on, scheduling practice and recording practice are all inside these figures.

Every figure above comes from the administrative records named here, at the granularity those records publish: a day, a month or a year. Coverage and definitions differ between countries and eras, so two sources are combined only where their documentation states the windows are separate, and the page where that happens says so.

Full method, leap-day treatment and definitions.

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