This chart comes from a post by Lane Kenworthy (http://lanekenworthy.net/2008/09/03/slow-income-growth-for-middle-america/)
It shows the growth of GDP per capita and median family income in the US from 1947 to 2007.
By the latter year median family income was approximately 61,000$.
Had it kept pace with per capita GDP, as it did till the mid 1970s, it would have been approximately 91,000$
A great example of how a simple graph can tell a compelling story