I have no data to back this up, but I suspect you are wrong. I believe that the majority of American adults (let's say age 18 and above) are guilty of many crimes and that the NSA is very capable of obtaining evidence to convict them. Some of these crimes people are well aware of, like drug use, speeding, or the obvious copyright infringement, but some aren't, like tax crime or breaking safety regulations.

As the quote goes, in a closed society where everybody's guilty, the only crime is getting caught. And when the government already has all the evidence it needs to convict everyone, then anything can essentially be made illegal by selective prosecution of unrelated crimes. Have you been protesting against the government's foreign policy? Suddenly you're in jail for the mistake you made on your taxes 5 years ago. Have you been active in an alternative currency like Bitcoin? Surprise, you're in jail for that movie torrent you seeded a few months ago.