#Chart of US birthdates finds Christmas, New Year’s Day least popular

What do Christmas Day, New Year’s Day, Christmas Eve and the 4th of July have in common? Sure, they’re all holidays, but they also happen to be the four least common birthdays in the US.

Austin, Texas business intelligence developer Bo McCready turned 32 this week, and celebrated in part by giving a gift to the internet: a data visualization showing the most and least popular dates for Americans to be born between the years 2000 and 2014, which he posted on Reddit.

“I was curious how common an Aug. 11 birthday is,” McCready told The Post of his own birthdate. He found that the answer was “relatively more common” — and in the process of crunching Social Security Administration data he also unearthed a number of surprising facts about other days.

“Superstition probably plays into how we schedule births: The 13th of each month is a little bit lower than the 12th and 14th,” he said, pointing to a likely drop in cesarean sections performed on certain days. “I also thought it was really interesting Sept. 11 seems to be lower than the other days around it.”

Data on 20th-century births further bolstered McCready’s superstition hypothesis. It was only after Sept. 11 became associated with a national tragedy, McCready observed, that children started being born notably less frequently on that date.

Reddit commenters also noticed that there were dips in birthrates at the beginning of September and at the end of November. “When families take vacations around Labor Day and Thanksgiving, you’re not seeing a lot of scheduled procedures,” said McCready.

While Americans don’t prefer giving birth on the holidays, it does appear to be a popular time for baby-making. The most common birthdays are Sept. 12, 19 and 20, respectively.

“When we look at births peaking in late summer, we can back up nine months and infer that conception is most common around the holidays, when days are the shortest and coldest,” he said.

“In general, the patterns really made me think a lot about how frequently we have scheduled births in the United States, whether it’s an induction or a C-section,” he said. “Seeing how holidays are so much lower than other days, it’s really apparent that those things must have a huge impact on overall birth patterns.” (According to recent data from the Centers for Disease Control and Prevention, C-sections comprise more than 30% of all American births.)

That certainly seemed to be the case when he welcomed his 2-year-old daughter Willow into the world.

“She was born on the evening of July 3,” he said. “In the hospital, the next day was the 4th of July and it was a ghost town.”