@Xanthippe_Voorhees the numbers for Eastern Christians vary quite a bit. There are various reasons, but different sources will give different numbers.
Total Eastern Orthodox range from 250m - 450m
Oriental Orthodox range between 85m - 110m
Only the Assyrians we can say are definitely at about 600k.
Including the 15-20m Eastern Catholics, we get the total number of Eastern Christians coming in anywhere from 350,000,000 at the least, to as many as 580,000,000.
Part of the problem is many of these Eastern Christians live in countries that were either formerly or are currently either communist or Muslim, so it’s difficult to get accurate numbers.