In how many years has Switzerland become largely urban rather than largely rural >
The next eight largest cities in the state , in order of descending 2007 population , are Aberdeen ( 24,410 ) , Watertown ( 20,530 ) , Brookings ( 19,463 ) , Mitchell ( 14,832 ) , Pierre ( 14,032 ) , Yankton ( 13,643 ) , Huron ( 10,902 ) , and Vermillion ( 10,251 ) .