USCIS's Office of Fraud Detection and National Security (FDNS) statistics.

FDNS site visits in 2009 (7/29/09 – 9/30/09): 2,028 resulting in 229 Notice of intent to revoke

FDNS site visits in 2010 (10/01/2009 – 6/1/2010): 14,324 resulting in 496 Notice of intent to revoke