[Fwirt]

Except this could get confusing because the year 1976 (for example) is actually in the 20th century.

[accrual]

That is a good point. The "ordinal" century doesn't exactly line up with the digits in a "YYYY" format, thus "CCYY" creates some ambiguity depending on how one defines "century".

I conclude my fanciness of using "CCYY" is not useful. :)