And taxes stayed pretty much just that way for the next 15 years, until the early 1960s. Importantly, this was one of the most successful eras in US economic history. The middle class boomed, the economy boomed, and the stock market boomed. And all with the top marginal income tax rate over 90%. This suggests that the Republican mantra about high marginal tax rates killing the economy is, well, a bunch of crap.