@leo-j
Are you serious? I have no data to back my theory up. But without a link I don't believe you. There is no way the PSP is that close to the DS in game selection. Every market leader has had a major advantage in its game catalog.
I call Shenanigans.
In fact a quick look at the two lists on wikipedia supports my theory, granted I am sure they are both missing games, however, that is probably an equal loss.
http://en.wikipedia.org/wiki/List_of_PlayStation_Portable_games
http://en.wikipedia.org/wiki/List_of_Nintendo_DS_games