The agency says in the memo that its systems monitor 1.6% of the world’s Internet traffic, and its analysts review .00004% of global traffic…

Another document from the Justice Department describes the legal basis for collecting the telephone metadata, such as the numbers dialed, the length and time of the calls. The government says the NSA phone data collection operated under court supervision, and that the database is only accessed for specific searches in counterterrorism investigations.

The document also explains why government lawyers say the program carried out under section 215 of the Patriot Act respects constitutional First and Fourth Amendment freedoms, which protect free speech rights and prohibit the government from unreasonable search and seizure.