Many retirees see their golden years as an opportunity to start a new chapter. In fact, most retired Americans (60%) plan to or already have done a “retirement reinvention,” according to a recent poll commissioned by IHG Hotels & Resorts and conducted by Talker Research.

Their retiree lifestyles might involve more travel, new hobbies or, if they’re among the 53% of retirement savers who plan to work in retirement to help make ends meet, a side hustle or two.

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That’s right: The retiree side hustle economy is in full swing. It’s also worth $6 billion, according to financial media company MarketBeat, which recently surveyed 3,000 respondents and analyzed public data to determine that retirees with side hustles earn an average of $379 per month.

Of course, how much money retirees make from their side hustles varies significantly depending on where they live.

MarketBeat’s research revealed that retirees with side gigs see the highest monthly earnings in Utah ($825), Wyoming ($550), Colorado ($513), California ($476) and Indiana ($460) and the lowest in North Dakota ($100), West Virginia ($164), Alaska ($200), Rhode Island ($236) and Maine ($250).

Related: Are You Actually on Track to Retire Well? A Financial Expert Reveals the Critical Milestones to Hit at Every Age — Plus 3 Common Oversights.

Retirees with side hustles are gravitating toward four popular options, per MarketBeat’s findings: starting a small business (32%), crafting and selling homemade goods (30%), trading or investing (22%) and freelancing (15%).

Retirees might also consider offering their services on gig platforms — a straightforward way to use their unique skill sets and talents to earn some extra cash.

Dan Weiss, 79, is a Minneapolis-based retiree who started a flexible side hustle providing furniture assembly services through Taskrabbit after he read a newspaper article about a young woman’s success on the platform. Weiss told Entrepreneur the gig earns him roughly $4,000 a month.

“It is very quick gratification,” Weiss said. “I have control of my calendar and work as much or as little as I desire.”

Additionally, retirees who don’t necessarily want to invest in their own tools or equipment to run a successful side hustle should look to app-based companies that give them what they need to start.

Larry Mack, a Dallas-Fort Worth area retiree, diversifies his income streams with his Kansas City-style barbecue catering business and a part-time side hustle driving for the luxury rideshare app Alto, which provides him with a company vehicle to transport his passengers. Mack’s Alto side hustle nets more than $1,000 a month.

“What more can you ask for?” Mack said. “I’ve seen places I didn’t know even existed. I don’t see it as work. It has taught me more about DFW. I haven’t had one bad experience while driving for Alto.”

Retired side hustlers spend an average of 10 hours and 24 minutes on their gigs every week, and although 34% say their primary motivation is additional income, 76% reported that their side hustles bring them happiness, MarketBeat’s research shows.

Related: Are You Actually on Track to Retire Well? A Financial Expert Reveals the Critical Milestones to Hit at Every Age — Plus 3 Common Oversights.

“The retiree side hustle trend is a testament to the evolving landscape of retirement,” MarketBeat founder Matt Paulson said. “It’s no longer just about leisure; it’s often driven by the need for financial security, along with a desire for purpose and fulfillment. Retirees are showing that there’s no age limit to innovation and entrepreneurship.”