Undercover police officers accompanied the decoys and issued citations when the minor was sold alcohol.

Stores on O'ahu had the highest rate of alcohol sales to minors at 18 percent, while stores on the Big Island had the lowest rate, at 6 percent. Convenience stores were the most likely place for minors to make a purchase, followed by grocery stores and gas stations.

"Youth often get alcohol directly or indirectly from adults," said Carol McNamee, a MADD board member. "Alcohol is the No. 1 drug of choice among youth."

On O'ahu, 56 of 317 stores surveyed for three months this year had employees who sold alcohol to minors. Of those 56 stores, 66 percent asked the decoys for ID and then sold them alcohol regardless of their age.

Stores located in the Kalihi and airport areas sold alcohol to minors 20 percent of the time, the highest rate on O'ahu, and stores in East Honolulu had the lowest rate of sales at 3 percent.

HPD Capt. Kurt Kendro of the department's Juvenile Services Division said underage drinking needs to be combated by both law enforcement and retail establishments. He said minors are most likely to buy alcohol after school."There needs to be law enforcement and education, we need that collaboration," he said.