More than 4.9 million people had government security clearances as of October 1, 2012, including about 1.4 million with "top secret" clearance, according to the Office of the Director of National Intelligence.
Nearly 800,000 government employees had "top secret" clearances, versus 480,000 contractors; the remaining "top secret" holders were not broken down.
http://www.businessinsider.com/israelis-bugged-the-us-for-the-nsa-2013-6