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It may be legal to buy and smoke marijuana in Colorado, but it’s still against the law to drive while high — and that’s a message an increasing number of people aren’t receiving.

Colorado’s largest detox network said Wednesday that the number of its patients busted for DUI while high on pot has nearly doubled, from 8 percent last year to 15 percent this year.

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“This percentage increase is significant because recreational marijuana legalization is in its infancy and there has clearly already been an impact on public safety,” Art Schut, president and CEO of Arapahoe House, said in a statement. “Our hope is that this new data will create awareness so that if Coloradans choose to use marijuana, they do not get behind the wheel.”

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Arapahoe House, which runs three detox centers in the state, compared data from Jan. 1 to May 31 in 2014 and the same period last year, when recreational marijuana sales were still illegal in the state.

In the six months this year, 197 of the around 1,311 people brought to the network’s detox centers after being caught for driving under the influence were high on marijuana.

In the same period last year, that number was 112 out of 1,324 brought in for DUI.

Colorado’s law allowing recreational sales of the drug in stores took effect Jan. 1, after voters approved an amendment to the state constitution in 2012. Medical marijuana has been legal in the state since 2001.

Arapahoe House Communications Director Kate Osmundson told NBC News the network expects to see an increase in the number of drivers busted for DUI while high on pot now that the drug can be sold in stores.

When people are brought by police to a detox center after being caught driving under the influence, staffers monitor them until they are sober enough to get home safely, usually by arranging a ride from family members, Osmundson said.

The network, which says it is Colorado’s largest provider of detox services, said its data shows the average person caught driving while high on marijuana is white, male, and 30 years old. Only one in five was female.

Denver Police did not respond to a request for comment.

It is illegal for drivers to operate a motor vehicle with 5 nanograms of active THC in their bloodstream, an amount the Colorado Department of Transportation says is comparable to the 0.08 blood-alcohol level used in cases involving booze.

In March, the state Department of Transportation launched a $1 million ad campaign to curb drugged driving.

— Phil Helsel