Answer this: Does the federal government record and archive more than 50% of private telephone conversations in the USA?

Glenn Greenwald reported on The Guardian, on May 4, 2013 that he believes that the US government monitors and records our telephone calls. He quotes Tim Clemente, a former FBI counterterrorism agent, saying, "All of that stuff is being captured as we speak whether we know it or like it or not."

So, is it true? Are most of our telephone calls recorded and preserved by the government? A simple "yes" or "no" answer would be great.