If religion had not happened at all what would the year be?

Clearly BCE and CE would be gone too.There would be some particular point in the history of some nation or empire that would have stuck as the starting point. I'd think it could have been the founding of Rome so we would be somewhere over 2500 after the founding now.

It might be, if we adopted it as commerce became world wide that the starting point would be picked to keep dates small (under 10,000) and far enough back to avoid negative dates in recorded history.That would make the Jewish dating pretty good and we'd have the year as about that of the creationists idea of the years since creation week .

It was two different times when they switched from the Julian calendar (after Julius Caesar) to the Gregorian (after Pope Gregory). The English didn't want to deal with the Popist new-fangled stuff but the calendar got to be 11 days out of whack with the seasons and finally they had to.Technically the year lengths are not exactly the same. The treatment of leap years makes them (on average) different. If they were the same length the calendar would have continued to diverge from the seasons.