Stop pretending to be wiser than an average 2nd grader. USA still follows the Gregorian calendar last time I checked. If you think 21st century started on January 1st, 2000 then you're just spreading lies, period.
There is no difference of opinion on Gregorian calendar or a century lasting 100 years instead of 99. Year 0 was NEVER included in this calendar or the Julian one.
You picked the wrong battle to fight. Now you're just exposing yourself as an average American who thinks Africa is a country. There is no debate for you to win. You're not changing the Gregorian calendar or putting it up for opinions anytime soon. It's not a statistical data to debate, period.
I don't contradict you specifically but I contradict obvious lies you're spreading from time to time (like in Kingdom of Lithuania which was in fact a Grand Duchy).