Your sophomoric, pseudo intellectial babble is very tiring. Latin is a dead language and who cares what the French said or will say. The only truth contained in your previous reply was contained in the first sentence.The rest was reminiscent of a little six year girl, in her first ballet costume, doing pirouettes in front of her parents with a look at me look, don't you think I'm cute.
Cute for a six year old but rather boring for an adult. (I'm guessing)
I stand by my previous explanation:
From 1/1/xxx0 thru 12/31/xxx0 encompasses one year, twelve months. The first year of any decade.I'm done. You're on your own.

David & Robert you are a couple of dummies.What happened to the twelve months between The stroke of midnight on 12/31/2000 and 12/31/2001.
Each year has twelve months including 2000. You are obviously the product of Government run schools.

The first year of the decade was 2000 not 2001.
Count the years.
0,1,2,3,4,5,6,7,8,9,equals 10 years or 120 months or one decade. Hope this helps.