The state government left Philadelphia in 1799, and the federal government was moved to Washington, DC in 1800 with completion of the White House and Capitol. The city remained the young nation's largest with a population of nearly 50,000 at the turn of the 19th century; it was a financial and cultural center. Before 1800, its free black community founded the African Methodist Episcopal Church (AME), the first independent black denomination in the country, and the first black Episcopal Church. The free black community also established many schools for its children, with the help of Quakers. New York City soon surpassed Philadelphia in population, but with the construction of roads, canals, and railroads, Philadelphia became the first major industrial city in the United States.

Answer this question, if possible (if impossible, reply "unanswerable"): When did the US government leave Philadelphia for D.C.?
1799