A lot, more than 20, probably closer to 30. Mostly Amells and Suranas with a fair number of Cousland's thrown in, a couple Dalish and City elves each. One each of the dwarven origins.
A lot of times I just made a character to play the origin story and then lost interest in them quickly once I got to Ostagar.
Full and complete playthroughs varied from complete, do every quest, even side excursions to the full extent, and some were just the main story playthroughs to get through the game. Full playthroughs were typically about 60+ hours I want to say?
What can i say, I really loved Origins and I'm retired. I don't have to spend my time tending kids or working for a paycheck, so i have plenty of time on my hands and a real love for Dragon Age.