The USPS traces its roots to 1775 during the Second Continental Congress, where Benjamin Franklin was appointed the first postmaster general. The cabinet-level Post Office Department was created in 1792 from Franklin's operation and transformed into its current form in 1971 under the Postal Reorganization Act.The USPS employed 626,764 workers (as of January 2014) and operated 211,654 vehicles in 2013.[2] The USPS is the operator of the largest civilian vehicle fleet in the world. The USPS has exclusive access to letter boxes marked "U.S. Mail" and personal letterboxes in the United States.In the 1960s African Americans were appointed as postmasters of the nation’s three largest Post Offices – New York, Chicago, and Los Angeles. By the end of the 20 the century African Americans comprised 21 percent of all postal employees, serving at all levels of the Postal Service.