In any case I'd say that you're focusing on the less relevant issue in estate taxes, if your concern is tax burden on the wealthy, for a few reasons:
a) The estate taxes in 1960 might have been just as easy to sidestep as the corporate taxes SST mentioned; I sure know that estate tax avoidance/"estate planning" is a huge and profitable industry for American law firms today. In other words, a 70% estate tax would effectively be quite small if one were capable of hiding 80% of their estate assets from the IRS.
b) Estate taxes are in fact slated to increase and align with the marginal tax thresholds for "ordinary income" (basically, your paycheck minus deductions)-- which has now been increased up to 40% for the top bracket as part of the new "fiscal cliff deal".
c) Estate taxes of course are only collected once per lifetime
I think the more insightful data comes from the Office of Budget Management, which measures
A couple things to take away from these figures:
- The Federal gov't has long relied overwhelmingly on taxing personal income (Individual+Payroll taxes), which has consistently accounted for 80-85% of all tax receipts since at least 1980; that number had risen steadily since contributing to only around 50% of total receipts in 1950.
- The Payroll Tax exempts any income above $110,000 per year ($90,000 from the year of your study)-- I believe only roughly 15-20% of American households earn more than $110,000. Therefore Payroll Tax is by far the largest "regressive" federal tax by magnitude; it makes up only a small portion of the federal tax burden for the rich and super rich. Which leaves...
- The "Individual Tax" is by far the biggest burden on the rich and super rich, as a percentage of income. It consists of annual income taxes above and beyond the payroll tax-- all the way up to 40% of marginal income for the aforementioned top ordinary income bracket (currently, the top bracket threshold is $400k/individual or $450k/family). The individual tax also includes dividends and capital gains taxes, which is another big source of income for the top 20% or so.
Since the new fiscal cliff deal, dividend taxes--relied on by investors in large, established, low-growth firms) remain at the low rate of 15%. Long-term capital gains (assets held greater than one year) remain at 15% for most people, but now will progressively increase to 20% for earners of ordinary income>$400,000. Short-term capital gains (stocks only held for <1 year) taxes remain at the individual or family's ordinary tax rate (again, 40% for the top bracket).
If you want to increase the tax burden on the rich, you will raise far more money by attacking the individual tax, rather than estate tax.
I will make a subsequent post to conclude my thoughts...