A quick link to a paper I found at the World Bank web site:When did inequality rise in Britain and America?
From the Abstract:
. . . income inequality rose in both Britain and America between 1977 and 1995. In America, it regained the old pre-1929 levels, contrary to the official figures. Second, wealth and earnings gaps widened sometime in America between 1774 and 1913. Third, inequality rose in Britain from 1740 to 1810, earlier than others have suspected . . .