Online annex: Inter-agency Task Force on Financing for Development (https://developmentfinance.un.org). Tax progressivity in OECD countries ,1981,1983,1985,1987,1989,1991,1993,1995,1997,1999,2001,2003,2005,2007,2009,2011,2013,2015,2017 Progressive Tax Capacity (average),0.11,0.10,0.09,0.09,0.08,0.08,0.09,0.09,0.09,0.08,0.08,0.08,0.07,0.07,0.08,0.08,0.08,0.07,0.07 Progressive Tax Capacity (median),0.09,0.10,0.09,0.08,0.07,0.07,0.07,0.08,0.07,0.07,0.08,0.07,0.07,0.07,0.07,0.07,0.07,0.07,0.07 Tax Rate Progression (average),0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,,,,,, Tax Rate Progression (median),0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.1,,,,,, Chart downloaded on 2019-10-17 18:56:20 from https://developmentfinance.un.org based on data from IMF Fiscal Monitor October 2017 Note: The average tax rate progression is the slope coefficient from regressing actual average tax rates on log of gross income. The progressive tax capacity index is calculated as twice the area between the Lorenz curve for income and taxation, using uniform distribution of income.