Eco­nom­ic inequal­i­ty in the Unit­ed States is the high­est it’s been in the last 50 years. In recent decades, the rich­est 1% of Amer­i­cans have accu­mu­lat­ed near­ly 40% of the country’s wealth. The net worth of just three indi­vid­u­als — Jeff Bezos, Bill Gates and War­ren Buf­fett—dwarfs that of the entire bot­tom 50% of Amer­i­cans. And it only seems to be get­ting worse.

How did we get here? In a new book The Tri­umph of Injus­tice: How the Rich Dodge Tax­es and How to Make Them Pay, authors Emmanuel Saez and Gabriel Zuc­man sug­gest the answer has much to do with changes to the tax code that have reduced the bur­den of tax­a­tion on America’s wealth­i­est groups and made it eas­i­er than ever for cor­po­ra­tions to evade pay­ing their dues.

Pol­i­cy pro­pos­als from 2020 hope­fuls like Eliz­a­beth War­ren and Bernie Sanders are seek­ing to change that. Warren’s ​“Ultra-Mil­lion­aire Tax” would impose a 2% tax rate on net worth in excess of $50 mil­lion, which becomes a 3% tax rate beyond $1 bil­lion. In oth­er words, any wealth between $50 mil­lion and $1 bil­lion would be taxed at 2%, but the 1,000,000,001st dol­lar (as well as any­thing beyond that) would be taxed at 3%. Sanders’ ​“Tax on Extreme Wealth” plan goes even fur­ther by insti­tut­ing a 1% tax rate on net worth above $32 mil­lion that ris­es steadi­ly to 8% on all wealth over $10 bil­lion. Warren’s cam­paign claims her plan would bring in $2.75 tril­lion in rev­enue. Sanders’ would like­ly raise even more, which he pro­pos­es to use as fund­ing for his afford­able hous­ing plan, uni­ver­sal child­care, and some of Medicare for All.

Here are nine sta­tis­tics from The Tri­umph of Injus­tice that show how tax injus­tice has con­tributed to inequal­i­ty in Amer­i­ca and the urgent need for reform: