Sometimes I get distracted by shiny trivia. Shortly before St. Patrick’s Day, I noticed that seven of my Facebook friends happened to celebrate their birth on that holiday. That seemed surprisingly high, so I went through and counted up the birthdays for all 459 of my Facebook friends who have their birthday listed. The results are interesting. I don’t know if they’re meaningful or not.

As you can see from the I-should-have-made-it-larger chart above, any given day is most likely to be the birthday of one of my Facebook friends. It is slightly less likely to be the birthday of none of my friends. That was the most surprising result: I would never have expected that 108 days a year are empty when there are 459 birthdays to go around.

St. Patrick’s Day is the most frequently-birthed day with seven, although June 4 has six. According to the New York Times, those are the 134th and 146th most common birthdays. The most common birthday for those born between 1973 and 1999 is September 16, yet none of my Facebook friends claim that day.

May and December are the most common months for my friends, both with 52 birthdays. January is the least common with 25, though February and November each have 26. February gets some credit for being the shortest month, but it is still among the three months with less than one birthday per day. January does claim the longest stretch of birthday-less days, with eight.

How about days of the month? The 31st has the highest average, due to the 5s contributed by March and May (interestingly, these are the only two days with 5 birthdays). In second place, is the 22nd, which has the highest total count at 24. The lowest is on the 20th, which only has 6 birthdays. Two days before and after are in the 20s, so it’s a notable dip.

The full spreadsheet is available in Google Drive if you want to make your own observations.