Inequality in the USA Distributional National Accounts: Methods and Estimates for the United States, Piketty et al. 2017 available at

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: