Four Southern Arizona businesses sold alcohol to minors during a recent undercover buying operation and that’s an improvement, officials say.

Nine teens between the ages of 16 and 18 volunteered to participate in the operation, which took place Friday night at 42 businesses in Sierra Vista, Benson, Tombstone and Bisbee, according to a Sierra Vista Police Department news release.

The businesses were chosen “based on previous liquor violations, citizen complaints and other factors,” the news release stated.

Officers with the SVPD and the Cochise County Sheriff’s Office accompanied the teens. They saw a nearly 43 percent decrease in illegal purchases compared to the last operation conducted in December.

“No deception or fake identification were used, and the volunteers carried IDs clearly indicating they were under 21 years of age,” the news release stated.

The businesses cited for selling alcohol to minors were Peter Piper Pizza and Buffalo Wild Wings, both of Sierra Vista; Stock Exchange Saloon in Bisbee; and Doc Holliday’s Saloon in Tombstone.

In the December 2013 operation, seven businesses were cited for selling alcohol to minors.

The Centers for Disease Control and Prevention, Monday, released the results of a new study that reveals underage drinking has declined to record-low levels in 2013.

The percentage of high school students who reported that they currently drank alcohol declined 31 percent, the lowest it has been since 1991.