I have compiled the corporate income tax rates since 1952 through 2021 and put them in a chart I hope is easy to understand. In doing this, I plotted the hypothetical tax bill of two corporations: one making $500K per year and one making $20M per year and plot the percentage of taxable income the tables said they should pay. I also decided to put per capita GDP in constant 2015 dollars on the chart, because I could. Here is the chart:
The chart shows the steady downward trend in the tax rates since 1952. The picking of 1952 was a little arbitrary, but I hoped it would be after the effects of the wars were out. The thing that struck me right away is the negative correlation between per capita GDP and the lowering of tax rates. So much for “trickle down”. I must say here, one of the tenants of statistical research is: “correlation is not causation”. As I was doing my research, it became clear rates were only part of the story. I will go into that soon, on another day.