American income tax rates from 1944 to 1963 were 92% [pdf].

To be truly comparative, the chart also needs to include, for each year, the median and average household incomes for each tax year as well.

Knowing that in 1917 those making over $2million were taxed at 67% is fine, but without converting $2million into todays dollar value, it is hard to compare the relative effect.

Read a great book about how destructive such high taxes are called The Way The World Works by Jude Wanniski.