I think a good followup would also be to share how many encounters you get in per session. I've been told that we fly through encounters. First, we play diceless, using the autoroll option in DM Genie, and that speeds up combat for us exponentially. And, we use a 12 second real-time rule for declaring actions in combat. I thought I should mention that to give a clearer picture of our gaming style. We also use Maptools, a virtual tabletop, that we'e found to be more efficient for us then when we used minis. That said, our average combat round (4 characters @ 4th level, v.s. 4 even creatures) takes 2-3 minutes. Battles average between 6-10 rounds, as we have a lot of outdoor encounters on very large maps. So out of a 6 hour session, about 2 hours is combat (we average 4-6 encounters/session), 2 1/2 hours of roleplaying, and at least a mandatory minimum of 30 minutes of OOC conversations and goofing around. I have a friend who runs a Core only campaign and he's told me they've had a single round take 10-15 minutes, even at lower levels. I think there are a lot of variables that come into play when it comes to how a group manages their time.
I would consider our group to be fairly dedicated gamers that are pretty balanced between combat roleplay/storyline roleplay. In my current main group of 5 members we have:
Me, DM, , 37, playing RPG's since around 1981
Scott, , 40, started with Chainmail '78ish
Mark, 41, Started with D&D '80ish
Aaron, 33, started as a newb with our group about 4 years ago
Michael, 38, started as a newb in our group, about 2 years ago
So a very long-winded answer to the original poll for us would be around 40%, having 4-6 encounters per session.
I'm really enjoying reading how other tables play their games!