Over 44 million American adults have a side hustle – that is, a way to earn extra money other than a main source of income – according to a new report from Bankrate.com. This includes 28% of younger millennials (ages 18-26), who are the most likely age group to have a side hustle. Click here for more information:

Eighty-six percent of side hustlers do it at least monthly, and 36% of those earn more than an additional $500 per month doing so. Frequency and amount earned tend to differ by generation:

• Of those ages 18-26 with a side hustle, 96% say they do it at least monthly, compared to 83% of those who are older than that.

• Millennials, as a whole (ages 18-36), typically earn less from their secondary source of income than older generations; only 19% with a monthly side hustle earn more than $500 per month, compared to 50% of those who are older.

• Younger Baby Boomers (ages 53-62) are the most likely age group to pull in at least an extra $1,000 per month.

Of those who earn money on the side, the majority (54%) use the extra cash to help pay for expenses, rather than as disposable income for other things. Though, how side hustle income is put to use varies across gender and political affiliation:

• About 7 in 10 women (69%) say they use the extra money from a side hustle to help pay expenses, compared to less than half of men who do the same (42%).

• Democrats and Independents are nearly twice as likely as Republicans to use the additional cash to pay for expenses (60% to 32%).

"A side hustle can be a great way to help pay the bills or pad your savings account on your own schedule," said Sarah Berger, The Cashlorette at Bankrate.com. "It's important to be smart about any extra income you earn. Pay down debt and take care of your monthly expenses first before adding anything to your shopping cart."