We work hard for it, spend it as soon as we earn it, and seem to be constantly chasing after it. “It” is money! The next time you pull out your wallet to make a purchase, consider this money trivia concerning those papers comprising U.S. currency.

George Washington’s face graces the $1 bill, but wife Martha Washington appeared on select $1 Silver Certificates issued in the late 19th century. Anyone featured on either paper or coin U.S. currency must be deceased.

The $1 bill is the most commonly printed by the U.S. Bureau of Printing & Engraving, accounting for almost 50% of all currency in circulation. The $1 and $20 bills, printed on paper which are a cotton-linen blend, are the most used in American commerce.

The highest denomination bill ever printed never made it way into anyone’s wallet. It was the $100,000 Gold Certificate used to transfer money back in 1934.

The average $1 bill costs 4.2 cents to print and lasts almost 2 years in circulation.