SEATTLE (AP) - As voters in Washington consider whether to legalize and tax marijuana for recreational use, a new study has estimated what pot prohibition cost statewide last decade: more than $200 million. The American Civil Liberties Union of Washington released the figure Tuesday, accompanied by an interactive map showing the costs by each county (seen below). The estimates are based on data from the Washington Association of Sheriffs and Police Chiefs, court filings and other agencies, and include costs from arrests, prosecution, public defense, jail and supervision. "People have probably guessed that we've been spending a lot in the war on marijuana," said Mark Cooke, policy advocate for the ACLU chapter. "This lets people see what is being spent at the county level. I think this is the first time that's been done." The study shows that each of Washington's 39 counties spent at least $100,000 on marijuana enforcement from 2000 to 2010. King County spent the most - nearly $35 million. Pierce County spent more than $21 million, Snohomish County spent $14.4 million, and Spokane County $12.7 million. Southwest Washington's Wahkiakum County spent just $106,000. The study did not take into account any revenues from criminal forfeitures in drug cases. Washington is one of three states - along with Colorado and Oregon - considering legalization ballot measures. Washington's Initiative 502, whose sponsors include Seattle City Attorney Pete Holmes and former U.S. Attorney John McKay, would allow the sale at state-licensed stores of up to an ounce of marijuana grown by state-licensed farmers. The marijuana would be taxed at 25 percent at three different stages, and state budget analysts say it could bring in as much as $1.9 billion over the next five years. Some of the money would be dedicated to the state general fund, while other portions would be devoted to health care, education and substance-abuse prevention. However, marijuana would remain illegal under federal law, and it's unclear how the Justice Department might respond if I-502 passes. The department could sue to try to keep it from taking effect, or seize any tax revenue as proceeds of drug deals. I-502 would not allow the public display or smoking of marijuana, and would redefine marijuana under state law so as to allow the growing of industrial hemp with negligible amounts of THC, the main psychoactive component of cannabis. The initiative also includes a driving-under-the-influence provision that has drawn the ire of medical marijuana patients, who say it's so strict that they essentially would never be allowed to drive, even if they're not intoxicated. The ACLU of Washington supports I-502, but the study was designed as an educational tool, not as part of the campaign, Cooke said. He said the statewide figures are extremely conservative because of inadequacies in the data, including that dozens of police agencies did not report or incompletely reported arrest information. So far, I-502 has drawn no organized opposition except from within the medical marijuana community. However, the Washington Association of Sheriffs and Police Chiefs has adopted a resolution opposing it on the grounds that the drug is harmful and that legalizing it for adults would send the wrong message to children. The association did not immediately return a call seeking comment on the study. Alison Holcomb, campaign manager for New Approach Washington, argued that the hundreds of millions of dollars spent on prohibition in the state have done little to deter marijuana use. "People don't necessarily have a concrete image in their mind of how marijuana enforcement plays itself out," she said. "Hopefully, people can see the impact in their counties and think about what else those resources could be used for."