Kenny dies in almost every episode, simply for amusement as he always dies in a humerous and graphic way, apart from when he actually died in series 5 where he was replaced on the introduction by Timmy, and by Stan, Kyle and Cartman by a series of boys in their class, until suddenly in series 7 Kenny returns, and when asked where he had been he simply said 'Oh just over there.'
The way I see it, Matt and Trey created Kenny, so they should be able to do whatever they want to him, even killing him numerous times.
Kenny Dino died in 2009.
Rob Kenny died in 2010.
Kenny Blatchford died in 1933.
Kenny Jenkins died in 2009.
Kenny Page died in 2002.
Kenny Hawkes died in 2011.
Kenny Sargent died in 1969.
Kenny Banks died in 1994.
Kenny Clare died in 1984.
Kenny Meadows died in 1874.
Kenny Hogan died in 1980.
Ramnath Kenny died in 1985.