They quit putting years at the end of every game since SNK went out of business in 2001 (I think) so KoF 2000 got delayed till late 2001.

Actually there'll be more than 12 now.

94
95
96
97
98
99
2000
2001
2002
2003
Neowave
XI
XII
Maximum Impact
Maximum Impact 2/ or KoF 2006
Queen of Fighters (or whatever that all female KoF fighting game was called for the Neo Geo Pocket Colour)

Total of 16 games. I think I'm missing a few tho'.