Between 1995 and 2007, Houston judges issued 3, 886 sealed orders for electronic surveillance.

FORBES: Too Many Secrets: Judge Says Almost All Law Enforcement Phone Tracking Never Revealed

That's because court orders under the 1986 law are almost always sealed, and the Internet provider is generally prohibited from notifying the customer whose data is searched.

WSJ: Court Order Seeks Email Data of WikiLeaks Volunteer Jacob Appelbaum