From George Monbiot in the Guardian
Between 1947 and 1979, productivity in the US rose by 119%, while the income of the bottom fifth of the population rose by 122%. But from 1979 to 2009, productivity rose by 80%, while the income of the bottom fifth fell by 4%. In roughly the same period, the income of the top 1% rose by 270%.
In the UK, the money earned by the poorest tenth fell by 12% between 1999 and 2009, while the money made by the richest 10th rose by 37%.
In his book The Haves and the Have Nots, Branko Milanovic tries to discover who was the richest person who has ever lived. Beginning with the loaded Roman triumvir Marcus Crassus, he measures wealth according to the quantity of his compatriots' labour a rich man could buy. It appears that the richest man to have lived in the past 2,000 years is alive today. Carlos Slim, the world's current wealthiest man according to Forbes Rich List, could buy the labour of 440,000 average Mexicans. This makes him 14 times as rich as Crassus, nine times as rich as Carnegie and four times as rich as Rockefeller.
The number of poor Americans hit a record 49 million in 2010.