Even as racial barriers have tumbled and the nation has grown wealthier and better educated, the economic disparities separating blacks and whites remain as wide as they were when marchers assembled on the Mall in 1963. When it comes to household income and wealth, the gaps between blacks and whites have widened. On other measures, the gaps are roughly the same as they were four decades ago. The poverty rate for blacks, for instance, continues to be about three times that of whites. The march took place at a time when the benefits of American economic growth were widely shared. Between 1947 and 1979, the wages of workers at all salary levels grew by roughly the same percentage. But between 1979 and 2007, incomes shifted drastically, with the top 5 percent of earners seeing annual salary increases more than three times the size of those in the middle, according to the Economic Policy Institute, a liberal research organization. Overall, 63 percent of total income growth went to the top 10 percent of households between 1979 and 2007.