Central Library was designated as a United States federal depository in 1884. As of 2018, Central Library selects about 48% of the depository item numbers (units of selection) available. Agencies and branches that are strongly represented in the collection include the President and the Executive Office of the President; Congress and its committees and agencies; the Census Bureau; the Geological Survey; and the cabinet-level Departments of Commerce, Defense, Education, Energy, Health & Human Services (HHS), Justice, Labor, State, and the Treasury.