Sales of legal marijuana jumped 17 percent to reach $5.4 billion last year, according to a new report. Sales could grow 25 percent this year, to $6.7 billion, according to the marijuana industry investment and research firm ArcView Market Research.

By 2020, sales of legal marijuana could reach $21.8 billion, Fortune reports. “I think that we are going to see in 2016 this next wave of investors, the next wave of business operators, and people who’ve sort of been watching or dipping their toe in, really starting to swing for the fences and take it really seriously,” ArcView CEO Troy Dayton said.

The report includes medical and recreational dispensary sales, as well as cannabis products sold through delivery services and medical marijuana “caregivers” who can legally grow and distribute the drug.

The increase in sales coincided with the first full year of recreational marijuana sales in Washington state, the article notes. Legal sales began in Oregon last fall. Recreational marijuana sales in Colorado increased by almost 68 percent from the previous year. Marijuana edibles, which are higher priced, account for some of the increase in sales.

Dayton said the biggest factor in growing marijuana sales will be new state laws allowing legalized marijuana. If California legalizes recreational marijuana in November, the result could be a large increase in sales, he noted. Medical marijuana is already legal in the state.