About 17% of D.C. residents were age 18 or younger in 2010, lower than the U.S. average of 24%. However, at 34 years old, the district had the lowest median age compared to the 50 states. , there were an estimated 81,734 immigrants living in Washington, D.C. Major sources of immigration include El Salvador, Vietnam, and Ethiopia, with a concentration of Salvadorans in the Mount Pleasant neighborhood.