90 percent of messages intercepted by US National Security Agency were not foreign targets but ordinary users, like you and me, from the United States and abroad. Nearly half of the files which contains names, email addresses or other details belonged to United States citizens or residents, which the agency concealed, or “minimized,” to protect those citizens’ privacy. But despite the NSA concealed 65,000 references to Americans names and email addresses, the agency found more than 900 additional email accounts were found unmasked.
Source: https://thehackernews.com/2014/07/90-percent-of-information-intercepted.html