[quote=Pyro V]
"According to the Elder Scrolls Online "Ask Us Anything" Forum [1], elves of all three kinds (Bosmer, Dunmer, Altmer) live about two or three times longer than the other races (humans, Orcs, Khajiit, and Argonians). A 200 year old elf is old, a 300 year old elf is very old. Anyone older than that has prolonged their life through powerful magic."Found this, hope it helps.
[/quote]

^That's pretty much the info I've heard as well, so I'll go with that.