This week marks the 100th anniversary of the passage of the 16th amendment to the U.S. Constitution, which made it legal for the U.S. federal government to impose taxes upon the income earned by Americans. Since income tax season in the United States has officially begun, we thought we'd mark the occasion by revisiting our original Form 1040 tool, where you can find out how much of the money you earned last year would have been taken from you by Uncle Sam back in 1913!

Back then, of course, you would only have had until the first of March to pay up - but then, income taxes were a lot less complicated back then, which is one reason why the federal government now gives you until the 15th of April each year to pay up, or else....

Excerpts from the Instructions

3. The normal tax of 1 per cent shall be assessed on the total net income less the specific excemption of $3,000 or $4,000 as the case may be. (For the year 1913, the specific exemption allowable is $2,500, or $3,333.33, as the case may be.) If, however, the normal tax has been deducted and withheld on any part of the income at the source, or if any part of the income is received as dividends upon the stock or from the net earnings of any corporation, etc., which is taxable upon its net income, such income shall be deducted from the individual's total net income for the purpose of calculating the amount of income on which the individual is liable for the normal tax of 1 per cent by virtue of this return.

19. An unmarried individual or a married individual not living with wife or husband shall be allowed an exemption of $3,000. When husband and wife live together they shall be allowed jointly a total exemption of only $4,000 on their aggregate income. They may make a joint return, both subscribing thereto, or if they have separate incomes, they may make separate returns; but in no case shall they jointly claim more than $4,000 exemption on their aggregate income.

Afterthoughts

Speaking of complexity, if we go by the CCH Standard Federal Tax Reporter, it takes 73,954 regular 8-1/2" x 11" pages in 2013 to explain the U.S. federal tax code.

Meanwhile, the mortgage interest deduction has always been with us! And so has the itemized deduction for all state and local taxes paid by taxpayers, but not the deduction for charitable contributions, which was added to the tax code in 1917 - just as income tax rates were being jacked up to pay for World War I.

Finally, the people least likely to be paying their fair share of income taxes in the United States live in households with incomes below $67,530. Coincidentally, that's where over half of the income available to be taxed is to be found in the United States. Just in case you ever wondered why President Obama was so happy to let his emergency 2% payroll tax cut expire on New Years Day of 2013....