The National Security Agency vacuumed up more than 151 million records about Americans’ phone calls last year via a new system that Congress created to end the agency’s once-secret program that collected domestic calling records in bulk, a report disclosed Tuesday.

Although the number is large on its face, it nonetheless represents a massive reduction from the amount of information the agency gathered previously. Under the old system, it collected potentially “billions of records per day,” according to a 2014 study.