9.
PokeRap, Johto PokeRap, and many other songs from the first two gens as well. Considering after that they didn't make many songs at all other than the openings. Such a shame.
Also I find it hilarious when people, for the later gens, say 'sing that Pokerap now' when, if you look at the Johto (and I think Hoenn actually had a Pokerap? idk I listened to it once and never again) Pokerap they only sang the Johto Pokemon haha.