Inequality in the USADistributional National Accounts: Methods and Estimates for the United States, Piketty et al. 2017 available at http://gabriel-zucman.eu/usdina
The paper concentrates on income inequality in the USA, both pre and post tax, including benefits through redistribution.
He exhibits the share of national income for the bottom 50% over time
The second image shows real income for the botton 50% flattening in the late 80s and that it has not recovered from the 2008 recession
The third is the share of the national income going to the top 1%, showing steady increase.
A paper in 2016 by Saez and Zucman at
addresses wealth as opposed to income: