How many seller's are flippers? (Buying to make a profit by redoing the whole house)
How many seller's are owners that have their houses up for sale for various reasons?

I have been on the market for over 8 months now...once we sell, we will move into a house we built earlier this year and use the money from this house to build another one. When we finish that, we will move into that house and sell the one we just finished...or at least that is the plan for now. So in a sense we are flipping, but plan to live in the house while we build the next one...etc.

I am not sure that there are any statistics to accurately answer your question. It would stand to reason that most houses are on the market by people who live in them as a primary residence. There are flippers, but these would be a minority.

if you really wanted stats, i guess you would have to see how quickly homes changed owners. Where I live, there are a lot of foreclosed properties that people are trying to flip or turn into rental properties. There is a house across that street that has been empty for over 13 years(& that's only as long as I have lived here & that house had never had anyone live there) About 6 months ago, someone finally bought it and in 3 months sold it to someone else for top dollar in this neighborhood. My guess is that it looks OK on the outside and inside, but there are a lot of hidden stuff waiting to happen.

As a homeowner, I'm not happy about either prospect. As discussed in another thread, renters tend not to take care of the property very well....

But the fact that someone owns something for a short time does not necessarily mean flipping either. I bought a house with someone and not long after we decided to break up and sell the house. Yes, we did make some changes to it and put money into it; however, we will lose all of that money because we only had the house for about 10 months at this point (6 months at the point we put it on the market)

I don't know what the statistics are but I would think the # of flippers would be small compared to homeowners selling a residence they live in to move to another residence to live in.

During the sellers market I would think the amount of flippers would be higher than it would be in todays market too.Money can still be made but a house doesn't turn over as fast as it did before so unless someone can afford to sit on the property and undetermined length of time they probably got out of that business and moved on to something else.
Of course this is JMO.