Historical US Income Taxes

In recent discussions about the US federal budget, much of the conservative rhetoric has pivoted on the argument that heavily taxing the wealthy is unfair.  The latest budget out of Congress added a new tax bracket, 39.6%, that applies to the wages of those earning more than $400,000 (single filers) or $450,000 (joint filers) instead of the old 35% bracket (1); this led to the infamous 'sad rich people' infographic in the Wall Street Journal (2).

These discussions piqued my interest in the history of income taxes in the US.  How do current taxes compare to the historical rates?  Thanks to the IRS (3) and the Tax Foundation (4), I can do more than wonder.  I used data from these sources to create my own infographic:
US historical income tax rates. y-axis is year (2013 on top); x-axis is earnings ($0-1,275,000); each color is 10%
This graphic represents the inflation-adjusted effective income tax rates in the US over the last century.  Effective tax rates have been much, much higher than they are today for most of the US' history.  From 1942 to 1981, taxpayers with wages over $1 million in today's dollars were paying 60-80% income tax; from 1944-1963, the top tax bracket was over 90%.  The Apollo space program, President Eisenhower's Interstate Highway System, education improvements beginning with the National Defense Education Act, payoff of World War debts, and all of the other projects of the Greatest Generation were in part funded by these taxes on the rich.

This doesn't take into account payroll taxes (Medicare, Social Security), state taxes, sales tax, or any other kind of tax, so I can't say how the overall tax burden has changed for the average American over this time period.  That being said, it's clear that the rich in previous generations haven't shied from contributing.

The graphic also doesn't take into account the various tax deductions available to eligible taxpayers; on this topic, however, I was able to find some interesting data on the history of the Personal Exemption (5):
It looks like the Personal Exemption was originally supposed to entirely exempt enough money to live on, but this concept didn't survive World War II.

The Google Spreadsheets in which I calculated the inflation-adjusted exemption data (6) and created the income tax graphic (7) are available.

(1) http://taxes.about.com/od/Federal-Income-Taxes/qt/Tax-Rates-For-The-2013-Tax-Year.htm
(2) http://online.wsj.com/article/SB10001424127887323689604578220132665726040.html
(3) http://www.irs.gov/pub/irs-prior/
(4) http://taxfoundation.org/
(5) http://taxfoundation.org/article/federal-individual-income-tax-exemptions-and-treatment-dividends-1913-2006
(6) https://docs.google.com/spreadsheet/ccc?key=0AiEk9zzYZVLgdFpQMXlaVkc1UVQ3bXBEdUl2S0tBTmc
(7) https://docs.google.com/spreadsheet/ccc?key=0AiEk9zzYZVLgdFNSd1QwVHhMbXR1VHd5M2Ryd25IN0E