U.S. Government Pinged AT&T And Verizon Combined Once Per Minute For User Data Last Year
That's just for AT&T and Verizon alone. As revealed in its first ever transparency report, AT&T reports 301,816 requests for user data from state, local, and federal authorities combined in 2013. Verizon received even more at 321,545. Added together, that comes out to 1.2 requests per minute.
You'll notice that only takes into account two telecoms; what about Sprint and T-Mobile, or even CenturyLink and Frontier, among many others? Unfortunately, the remaining ones that have previously disclosed data requests are from 2012. You could combine those with more recent figures from 2013, but the result wouldn't be accurate.
We can narrow our focus to 2012, though the problem there is that landline companies don't have transparency reports for that year. Neither does Sprint. However, for the three remaining major wireless carriers in the U.S. (AT&T, T-Mobile, and Verizon), total data requests in 2012 came out to about 2.2 per minute.