Up until last week I'd've said that the decade starts with year 0, not year 1 (because a set of 10 goes 0-9, not 1-10) but now that I've learned that in our current calendar system, AD/CE started with year 1 (the day before 1 Jan 1 AD is 31 Dec 1 BC), it makes more sense that the decade starts on 1, not 0.
@danieljsummers indeed! Blissful unawareness was the best
@levisan nobody lived through that year and called it as such. I think it makes more sense to just say the first decade was a year short because we changed calendars along the way. Matching the tens column makes so much more sense IMO.
@levisan Welcome to the realm of those of us who know differently, yet have to suffer through the "next decade" stuff. At least you were blissfully unaware for the "next century"/"next millennium" celebrations... :)