It has been nearly four years since Colorado and Washington legalized recreational marijuana, and the good times are still rolling.

Sales on April 20 — also known as 4/20 — increased dramatically in both states this year compared with 2015 and average daily sales.

As more states have legalized marijuana in some form and advertisers outside the industry have begun to embrace the holiday, 4/20 has evolved into a more mainstream event than its counterculture origins.

In Colorado, retail sales were up 53% year-over-year, reaching $7.3 million, breaking the previous daily record of $6.1 million set on September 16, a tax holiday, according to cannabis industry data firm BDS Analytics. The holiday bolstered sales for the entire month, breaking the monthly sales record with $117 million-worth of sales in April, up from $101 million in December. In Washington, the $5.5 million in sales on April 20 was double the amount of sales on that day in 2015, according to data from Headset, a company that tracks cannabis transactions.

Twenty-four states have legalized medical marijuana — most recently, on June 8, Ohio Governor John Kasich signed a bill legalizing medical marijuana into law — and four states and the District of Columbia have legalized cannabis for recreational use. Colorado and Washington were the first states to pass recreational marijuana laws in November 2012.

Marijuana concentrates — an increasingly diversified product category — saw 133% growth in Colorado sales for the month of April, reaching $27 million and making up nearly a quarter of all product sales, according to BDS Analytics. In Washington, concentrates sales on April 20 increased nearly 250% from average sales levels, according to Headset.

During the 4/20 holiday in Washington, hourly sales increased nearly 140% from average sales, with about 70% more items per transaction, according to Headset. 4 p.m. was the peak selling hour that day.

Nationwide, legal marijuana sales reached $5.4 billion in 2015 and are expected to hit $6.7 billion this year, according to cannabis analytics firm New Frontier and Arcview Market Research. Support for marijuana legalization is also continuing to grow, with nearly 90% of Americans in favor of legalizing medical cannabis and 54% for allowing any use of marijuana in the U.S., according to a June poll conducted by Quinnipiac University.