"Medieval theologians debated how many angels could fit on the head of a pin. Modern economists debate whether American median income has risen or fallen since the early 1970s. What’s really telling is the fact that we’re even having this debate. America is a far more productive and hence far richer country than it was a generation ago. The value of the output an average worker produces in an hour, even after you adjust for inflation, has risen almost 50 percent since 1973. Yet the growing concentration of income in the hands of a small minority has proceeded so rapidly that we’re not sure whether the typical American has gained anything from rising productivity."
-- Paul Krugman, The Conscience of a Liberal, p 124.
(Definitely a book worth reading.)