I didn't complete the survey, "How often do you create new personas"? That isn't a numerical value for me, they are created if and when needed. If I'm working on a new product then I would get the internal understanding of the userbase, and create proto personas. I'd then go out in the wild, find these people, interview them, and turn them into something more concrete.
As you can perhaps tell I can't say 1,2,7,12 to that... it depends.
The following question was, "How many people are involved when you create personas"? By 'create' do you mean how many people put together the physical deliverable, or how many people are involved in understanding the user? I'd do a UX questionnaire to try and find out what business knew about the people who they believe will be using the product, then I'd go out and find people to speak to - again if you mean this, then it depends.