NEW YORK – Americans can't get enough of donuts, eating more than half a billion dollars’ worth in convenience stores alone in 2014, reports CNBC.

Today is National Donut Day, and convenience stores are one of the most popular places for consumers to buy these tasty sweet treats, which “hold their own” in the bakery section, according to IRI. The Chicago-based research firm reports that in 2014, convenience stores sold some 391 million donuts (on an annualized basis) for sales of about $580 million.

Massachusetts-based Cumberland Farms, as well as national retailers like Dunkin’ Donuts and Krispy Kreme, will commemorate the holiday by offering guests a free donut of their choice with a beverage purchase – or in the case of Krispy Kreme, no purchase is necessary, while supplies last.

Many say that National Donut Day was originally established in 1938 by the Chicago Salvation Army to honor women who served donuts to soldiers during World War I, although the exact origin of the donut is somewhat murky. CNBC describes the donut’s origins as "a convoluted past that involves Dutch immigrants, Russian exiles, French bakers, Irving Berlin, Clark Gable and a certain number of Native Americans," according to Smithsonian magazine, which also credits Elizabeth Gregory, a mid-19th century New England ship captain's mother, "who made a wicked deep-fried dough that cleverly used her son's spice cargo of nutmeg and cinnamon, along with lemon rind," as the likely pioneer of the donut.