I know signs but I sign SEE, Most people I've seen in the Deaf Community in my hometown signs ASL only without voice, that's because they're older folks, But I'm not sure about the younger folks because they're only involved with sports in the Deaf Community. I haven't seen them hanging or social with the older folks at the Deaf get-together events.
I'm not certain about the percent and numeric of people that knows only ASL, so I cannot comment that.
ASL is my second language after English. I sign PSE and most deafies I meet either sign ASL or PSE. My hubby sign ASL which is not a problem for me. There was a poll on this subject here a month ago or so.
Same here, only I use mostly ASL/SEE now... When I first started learning sign language, it was ASL (wow, just figured it out -- it has been 40 plus years that I have been signing! So Cheri I guess you could put me in the older folk category -- LOL):