dom, here are a few of yao king's #'s (i stress his because he gives you the cards and the %'s, and his book is very, very good).

in early position (assume the first 3 - i forgot but i think so). also, i can't remember what type of game he is talking about but my sense is typical. fairly loose, fairly passive.

first in: play 7.5% of hands
limper already: play 9.4% of hands
raise already: play 3.8% of hands

obviously, your actually play rate would depend on play of other players, but note these are all under 10% so your average will under 10%. very few raises and you'll be around 8%... but still, this is throw away tons and tons of hands.

"play" = either call or raise (obviously he's clear on each hand).... first in and raise already is heavily weighted towards raising yourself, and limper already is weighted towwards you limping... the % of