The Department of Homeland Security released its annual FOIA report for 2016. Acting Chief FOIA Officer Jonathan R. Cantor said in the report that DHS receives more FOIA requests than any other department, accounting for 40% of all FOIA requests made across the federal government. The bulk of these requests are made to U.S. Citizenship and Immigration Services (USCIS). Cantor also said that DHS's sizeable FOIA backlog has reduced despite an increase in requests.
The full report can be found on the DHS website.