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Where can I get exact date of birth data for the US?


This user has administrative data with potentially questionable data - very few births on January 1. Is that plausible?

Public use data from the natality detail files has exact dates of birth for the years 1973 – 1988. From 1989+, NCHS had confidentiality concerns, which means that only month and day of the week are available. That is also when geographic detail started disappearing.

A New York Times story made a file available, which shows month and day of birth for the period 1973 – 1999, without naming the original source.

Story: How Common Is Your Birthday

Here is a nice heat map of these data, which illustrates the seasonality of births in the US. And, holidays are pretty rare dates for births (Jan 1, Dec 25, and Jul 4 rank 364, 365, and 361 out of 366 respectively). Not surprisingly Feb 29th, which only occurs every four years ranks 366th..

Heat Map of Birthday Frequency, 1973 – 1999

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