Knowing how much marijuana people consume is now a very important statistic for officials in Washington and Colorado. That number can help them make sound decisions about how to regulate the supply side of the country’s first recreational marijuana markets. And on Wednesday a non-profit think tank released a report showing that Washington residents consume far more weed than the state initially thought.

In 2012, the Washington Office of Financial Management estimated that residents were consuming about 85 metric tons of marijuana. The RAND Corporation now estimates that the number is closer to 175 metric tons. That’s very roughly the difference between about 25 and 50 joints per resident each year. “You need to have a good idea about consumption to make decisions about licensing, how many distributors to allow, how many retail shops,” says Beau Kilmer, the lead researcher on the project. “And it’s important to have this…