I would say that those numbers are very close to being correct. We have seen it at the club and also at convention and in our travels.
Many people call theirself "swingers" yet they really do not swing, they just hang out and watch Swingers.
When we where in Florida I think the numbers where closer to 90% to 95% watching and very few really playing unless you count the women making out on the dance floor during dances.
We even made some major rule changes in Jan. at the Rooster because so many people would fill up the group room and couples only area just watching. One or two couples would play and 40 fully clothed couples would watch. Now if you want to use the couples only area you must be naked. You can still just watch but there is no clothes allowed in that area anymore. Has cut down on the usage but now 12 to 15 couples use the area and they are PLAYERS! Sometimes less is much better. Yes, we lost a few people over the new rules, many of them complaining in our forums without ever coming out and checking out what it was like but the owners did not see it as a loss. They saw it as a return to what the Rooster was built for, a swing club, not just a cheap peep show.