Probably 5 or 6, though I'm trying to get myself to focus on just one.
Just tooling around, I go from one story to another as the mood strikes me. But if I'm on a deadline, I can focus on one story and just soldier through until it's done. I know that sounds like it's some horrible experience, but I love it when I'm in the moments of a story. Does that make sense?
It just feels good to be with those characters and explore their world, sometimes I don't want it to end so I stretch out the writing and let myself procrastinate. When I just bull my way through a story, it's like all the pleasure of writing is combined so it's just like one really big hit. It feels great to be finished and for a couple of days I walk around in a daze, then it's over and I feel sad until I get into something else.