From 1933-1980, the average top tax rate was 77.8%. For sixteen of those years, it was 90-94%. That tax applied to personal income above $3.2 million, in today's dollars.
Those rates are enormously successful because, when facing a 90% tax rate, millionaires will do ANYTHING to avoid paying that tax. They consult accountants, and the accountant responds, ‘You avoid it by investing in things that one can write off as a business expense: buying new equipment, stocking up inventory, opening a new factory floor, refurbishing an old one – or by HIRING NEW EMPLOYEES.’ All of that creates jobs, stimulates manufacturing, provides workers with income that they can then spend – continuing the cycle of consumption and economic growth. It's good for the company, for the worker and for the country.