Do you know;
Christmas on December 25th is not celebrated by Eastern Orthodox churches that still live by Julian calendar, so Christmas there is on January 6–7th.
These churches are dominant in Greece, Russia, Ukraine, Belarus, Bulgaria, Serbia, FYR Macedonia, Romania, Moldova, Armenia, Georgia and noticeable in Baltic countries, Ethiopia and Egypt (Coptic) and Syria (Assirian church).
It is noteworthy that in Eastern Orthodoxy Christmas is only the second most important holiday, the first being Easter (Resurrection).
Also Christmas is not an official holiday and is not celebrated in all countries that have nothing to do with Christianity at large:
Morocco and Sahrawi, Mauritania, Senegal, Mali, Algeria, Tunisia, Libya, Chad, Egypt, Sudan, Somalia, Eritrea, Israel (apart from Christians), Turkey, and almost all other Asian countries.
In Asia there are exceptions:
Philippines that is 80% Catholic, Singapore, Macau and Hong Kong that were colonies long enough so that it deeply influenced their culture (but there Christmas is not central, just another big holiday of just another, if very prominent, culture)
South Korea where there is quite a number of Protestants, and Japan where it's as much a shopping time as in the USA but no church apart from relatively few devout Western Christians.
At that, in the latter five countries, especially Korean XMAS and Japanese Kurisumasu hold much more secular commercial meaning than religious, and for the most part neither Christmas that shuts down the West for a week, nor the New Year that shuts down Russia for almost two weeks, are holidays.