1913 IRS income tax form.

“This return shall be made by every citizen of the United States, whether residing at home or abroad, and by every person residing
in the United States, though not a citizen thereof, having a net income
of $3,000 or over for the taxable year, and also by every nonresident alien deriving income from property owned and business, trade, or
profession carried on in the United States by him.

“The normal tax of 1 per cent shall be assessed on the total net income less the specific exemption of $3,000 or $4,000 as the case may be.”

http://www.irs.gov/pub/irs-utl/1913.pdf

$3,000 in 1913 equals $69,767.44 today

http://www.davemanuel.com/inflation-calculator.php

At www.fark.com