That's a 54 percent drop since 1991 and it appears northwest Iowa has followed that trend.
"The number of youth drinking has gone down dramatically since 1976 -- drug use, too," said Mary Sloan, prevention supervisor and consultant for Compass Pointe Behavioral Health Services in Storm Lake and Spencer. "Ninety percent of 12th graders at that time had used. That number is down in the 58 percent range now. A decline is also evident in the past 20 years."
From 2002 to 2010 alone, the percentage of 11th graders who reported driving after using alcohol or other drugs was cut in half, from 14 to 7 percent, according to Iowa Youth Survey data.
Still, Sloan is not comforted by regionwide, statewide or nationwide data.
"What we do see from the same CDC report is the kids who are using alcohol are using five or more drinks in one night," Sloan said. "That's critical because of impairment. With their age, they do not perceive impairment like we perceive impairment. It has to do with brain development."
Even with a designated driver, Sloan is concerned about impaired teens.
"The 'Don't drink and drive' message began a long time ago,'" Sloan said. "The message was also, 'Get a designated driver.' I have huge issues with that. When you have a designated driver, you also have designated drinkers and they're given to drink as much as they can and want. That increases their impairment and also distracts the driver."
Regardless, drinking and driving amongst high school students continues to decrease, largely due to education, Sloan said.
"The reason for that decline is the message they've been getting from all the prevention information out there," Sloan said. "Also, in our area, law enforcement picks them up when they break the law. That's a huge deterrent."
While local law enforcement officials are unsure of the county's 20-year change in percentage due to changes in reporting, they note the numbers have improved.
"The attitude has changed," Spencer Police Chief Mark Lawson said. "We don't have as many parties involving alcohol; unfortunately, we have parties involving other things. But big parties are too easy for law enforcement to be notified. I think the parties are smaller and less noticeable. Out in the country, they can get away with more because the odds of being seen and heard are less."
Clay County Sheriff Randy Krukow remembers when that was not always the case.
"Back in the '70s, '80s and '90s, we'd have parties with more than 100 people at them," Krukow said. "That was not unusual in town. I just remember those times. In the '80s, the police department bought video cameras because, believe it or not, people would not tell us their real names."
The national study points to changes in graduated driver-licensing systems, zero-tolerance alcohol laws and parental involvement as effective deterrents.
While Lawson and Krukow acknowledge those factors in the improving drinking-and-driving stats, they are afraid another driving issue is causing even more of a problem now.
"Distracted driving is way up," Lawson said. "You just sit at a red light and see people texting. The school kids we can pull over, and we do. ... A lot of people get called in for being all over the road. Much of the time, there's no drugs or alcohol involved, but there's a cell phone right next to them. It's a tragedy waiting to happen and it is happening."