The short answer: No one knows for sure.

The longer answer: Not very many, say protesters and police officials, although the encampments have spread with lightning speed beyond their spawning ground in Lower Manhattan, where a loose coalition of protestors began assembling in Zuccotti Park near Wall Street on Sept. 17…

“I would guess that there are maybe 200 to 300 people sleeping here now,” said Matt Phillips, who has been in McPherson Square for the past three weeks. “It’s really kind of hard to say for sure because people come in and then go out.”…

The onset of winter will probably pare the number who stay around the clock, Jewler said. “But even if there are 20 to 30 of us in the park in the middle of the winter, it’s going to be enough. When spring comes, new people will join us.”