NSA collected 500 million U.S. call records in 2017

The U.S National Security Agency collected more than 500 million phone call records of Americans last year. This number more than tripled the number of gathered phone calls in 2016. The sharp increase occurred during the second full year of a new surveillance system established at the NSA. This new system was established after U.S lawmakers passed a law to limit its ability to collect such records in bulk.