Marijuana sales: Though 37 is the average age of a consumer, millennials make the bulk of such purchases. Just over 50 percent of recreational marijuana consumers are ages 21 to 34. Pictured: An employee collects money while holding packages of marijuana at Top Shelf Cannabis in Bellingham, Washington, on July 8, 2014, the first day of recreational sales in the state. (David Ryder, Getty Images file)

Take a guess. This is how much an average legal user spends on marijuana each year

Increasingly lax marijuana legislation may be cheered loudest in college dorms, but it’s the professor-aged ganja enthusiasts who are the average consumers of the legal stuff.

Headset Inc., a cannabis intelligence firm, reviewed about 40,000 legal marijuana purchases made in Washington State from September 2014 to July 2016. The Seattle-based company determined that the average recreational weed consumer is a 37-year-old man who buys traditional marijuana buds. The median spend by this customer was $647 annually, with an average of 19.5 days between purchases.

Though 37 is the average age of a consumer, millennials make the bulk of such purchases. Just over 50 percent of recreational marijuana consumers are ages 21 to 34, Headset found. Older generations are unlikely to stop at the legal dispensary: Fewer than 10 percent of the purchases reviewed in this report were made by those older than 60.

Customers in their twenties spent a median of just $27 per visit to a dispensary but made trips more frequently than other generations, a median of every 16 days compared to every 18.2 days for those in their thirties and 20 days for those in their forties. The median spend per trip also increased with age, topping out at $64 for those in their eighties. The biggest median annual spenders are members of Generation X: Users in their forties spent $823 in the last year and those in their fifties, $753.

‘”As you’re older, you might have more money to go and make bigger purchases,” explained Headset co-founder Cy Scott. “The millennials might be out and about more; they can drop into [marijuana dispensaries] more often. Older people might just plan more.”

The type of marijuana that consumers are looking for doesn’t vary much with age. Bud is most popular across the board, followed by pre-rolled joints, vapor pens and edible products (such as brownies) infused with marijuana.