From ACLU - http://www.aclu.org/...
between 2009 and 2011 the combined number of original orders for pen registers and trap and trace devices used to spy on phones increased by 60%, from 23,535 in 2009 to 37,616 in 2011. During that same time period, the number of people whose telephones were the subject of pen register and trap and trace surveillance more than tripled.
Not just that, the Justice Depart doesn't submit the annual reports it is required to.
When no reports surfaced in 2010 and 2011, the ACLU filed a FOIA request to obtain them. After our request received no response, we filed suit to enforce it.