The week surrounding 4/20, the pot smoker's holiday, is the marijuana industry's cash cow. But how much money does the holiday bring in?

Dispensaries across Colorado are expected to see sales increase to over $5 million a day from April 17 through 20, a 25 percent increase up from $4 million per day during the same time period last year, according to a report by data firm BDS Analytics. At least one day is expected to exceed $6 million this year.

Total sales on 4/20 in 2015, which was on a Monday, were 2.7 times the average sales seen on any Monday last year in Washington state. The Friday before 4/20 brought in 14 percent more sales than average Fridays throughout the year, according to a report by Headset, a Washington-based company cofounded by marijuana tech entrepreneur Cy Scott.

Scott says 4/20 saw the biggest spike in sales than any other date in Washington. The closest runner up was the Friday before Memorial Day, which only saw a 1.4 times increase in average sales.

The data from Headset found that 4/20 does not only bring more people into pot shops but each customer buys more on average. Scott says there were 58 percent more transactions on 4/20 than the average Monday, but the average "basket size" on 4/20 was $46.20, which is 33 percent higher than an average Monday basket of $34.80.

The majority of customers are reaching for edibles, sales for edible THC products was up 189 percent on 4/20 compared to 107 percent increase in flower. Pre-rolled joints were in 40 percent of baskets on 4/20 compared to 25 percent daily average. As for edibles, 30 percent of baskets contained edibles compared to 12 percent daily average.

The bottom line: 4/20 might have started as a day to protest marijuana laws but it has now been branded and sold back to stoners. Happy 4/20!