http://news.yahoo.com/s/ap/20110308/ap_on_re_us/us_census_america_s_heartland The West is now home to the four fastest-growing states - Nevada, Arizona, Utah and Idaho - and has surpassed the Midwest in population, according to 2010 figures. California and Texas added to the southwestern population tilt, making up more than one-fourth of the nation's total gains since 2000.