From a quick scan and count of my profile's game collection...
54 third party games.
25 first party games.
Some games, like F-Zero, Star Fox Assault, and Donkey Konga were made by third parties. Some games are by former second party devs like MGS: TS, Eternal Darkness, and Cubivore. So if those count as third party games, the list would be closer to 60 third party games and under 20 first party.
"I feel like I could take on the whole Empire myself."