I've spent three weeks there all told, a week each in early December, early November and mid October and will attest to those stats, however Fort Wilderness was near capacity while the parks were light.
If you're thinking of going in October that's when they hold their food and wine festival at Epcot. Free wine for all, unless you're good with being around some really drunk people might want to avoid that time frame. I had more than a couple of bad experiences because of the drunk people.
Now-2014 Sierra 346RETS 5er BUB
Then-2002 Keystone Springdale 286RLDS TT
Nights camped in 2014-28, 2015-127, 2016-10