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 recent report from Bankrate.com. That includes 28 percent of younger millennials (ages 18 to 26)—who are the most likely age group to have a side hustle.

Eighty-six percent of side hustlers do it at least monthly—and 36 percent of them earn an additional $500 per month (or more) by doing so. Frequency and amount earned tend to differ by generation:

• Of those ages 18 to 26 with a side hustle, 96 percent say they do it at least monthly, compared to 83 percent of those who are older.
• Millennials as a whole (ages 18 to 36) earn less from their secondary source of income than older generations. Just 19 percent with a monthly side hustle earn more than $500 per month, compared to 50 percent of those who are older.
• Younger Baby Boomers (ages 53 to 62) are the most likely age group to pull in an extra $1,000 or more 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. But this, too, varies across gender and political affiliation:

• Nearly seven in 10 women (69%) say they use the extra money to help pay expenses, compared to less than half of men (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,” says 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.” Check out the complete survey at bankrate.com/cashlorette/side-hustles-survey. iBi