So, I was going to do that math but it's 65 fucking countries and I'm bored but I ain't got that much battery left on my phone.
At one time Britain ruled over 1 out of every 5 people on the planet. If we carry that forward to today it's roughly 1.6 billion people. Let's call that the lower bound.
If we take the average population of any given country, which is fair given that China wasn't but India was one of them, and divide that by the number of countries and then multiply it by the number Britain used to rule, we get 2.6 billion.
Let's call that the upper bound.
There are roughly 2.6 billion christians worldwide. But not all of them celebrate Christmas. In the US, 85%-95% do. Let's just use that for the upper bound and say 2.2 to 2.5 billion people celebrate Christmas worldwide. Let's say 50% is the lower bound, at 1.3 billion people.
Which means that it's possible, and not even unlikely that more people celebrate independence from Britain than celebrate Christmas.