This first graph shows the relative increase in the incomes (inflation adjusted) of the top 1% of income earning households, the middle 60% and the lowest 20% (percentages, presumably, approximate) since 1979.

This second graph shows a more detailed picture of the relative increase in the incomes (inflation adjusted) of households in the 95th , 80th, 60th, 40th, and 20th percentile since 1949. Note how household incomes were rising at about the same rate prior to 1970, at which point those households in the 95th percentile started out growing other percentiles, those in the 20th stayed stagnant, and those in between were somewhere in between.

I borrowed these graphs from Lane Kenworthy, who also offers a truly excellent and detailed explanation of the measures.

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