Philip Bump at The Atlantic attempts to answer an important question: what exactly is Santa's Christmas Eve workload? He considered both the number of Christian children in the world and the geographic distribution of those children and reaches the following conclusion:
There are just over 526,000,000 Christian kids under the age of 14 in the world who celebrate Christmas on December 25. In other words, Santa has to deliver presents to almost 22 million kids an hour, every hour, on the night before Christmas. That's about 365,000 kids a minute; about 6,100 a second. Totally doable.
Especially when you consider the uneven distribution of kids in the world. Santa needs to hit 22 million kids every hour. If Santa starts at the International Date Line and heads west, the first four time zones he passes barely contain that many kids waiting for presents. He's already got three hours in the bank. Until, you know, he gets to Europe, which kind of breaks his schedule.
Bump offers a few caveats: not everyone celebrates on Dec. 25; some Christians don't celebrate, while some non-Christians still expect a visit from Santa, etc. Overall, though, we think it's a pretty good estimate -- check out the post for detailed graphs.