As others have noted, there's probably not an accurate count as not all fill in the survey. All of Florida has a sizable population of seasonal residents.
The attached article estimates that 1 million of Florida's 18-million plus 2010 population were seasonal residents.
Florida State Demographics | eHow.com
Doubt the number of seasonal residents in TV would hurt TV sales as snowbirds are a well-known fact of life about Florida. As in all of Florida, there is not a good way to calculate the percentage of PT vs FT residents. TV is similar to other destination communities in Florida in that many of the full time residents started out as snowbirds or snowflakes.