Here's a startup idea: Uber, but for providing the government with data on millions of people.

Uber, the ride-hailing behemoth, revealed on Tuesday that it provided data on more than 12 million drivers and passengers to U.S. law enforcement in the second half of 2015, in response to 33 data requests.

The data is part of Uber's first transparency report, showing the level of cooperation with U.S. law enforcement. With this release, Uber joins a fleet of tech companies, including Google and Facebook, which have released similar reports.

"The report shows that we comply with the majority of law enforcement requests, while ensuring they go through the proper legal process," the company said in a blog post announcing the report.

The data requested may vary, as Uber explained in its report: "These agencies may request information about trips, trip requests, pickup and dropoff areas, fares, vehicles, and drivers in their jurisdictions for a given time period."

The timing of the report did raise some eyebrows, coming just moments before Facebook's big F8 conference kicked off, effectively overshadowing the news.

In total, Uber received more than 400 requests from federal and state law enforcement between July and December of 2015. Of those, Uber provided at least some data in more than 80% of cases.