The number of teenagers who smoke and drink alcohol is declining, but more and more young people are consuming soda and fast food, according to a survey by the Korea Centers for Disease Control and Prevention.

The group polled 72,435 teenagers between the ages 13 and 18.

According to the finding, smoking among teens has decreased to 9.7 percent this year, the lowest since 2006.

In 2009, 12.8 percent of high school and middle school students polled admitted to smoking. That figure stood at 12.1 percent in 2011, and 11.4 percent last year.

Researchers considered a respondent to be a smoker if he or she smoked more than once a month.

Among the 9.7 percent who smoke, 4.8 percent of them said they lit up daily.

Boys were much more likely than girls to pick up the habit. Of male respondents, 14.4 percent smoked, while only 4.6 percent of female students did.

The report, jointly researched by the Ministry of Health and Welfare and the Ministry of Education, said teen smoking is more prevalent in vocational high schools than those focused strictly on academics.

The survey also found that fewer teens are consuming alcohol.

The underage drinking rate from the same survey stands at 16.3 percent, an all-time low.

About 28.6 percent of teens drank in 2006. That figure consistently dropped each year since. Only 21.1 percent said they imbibed in 2009, and 20.6 percent said they drank underage in 2011.

But while drinking and smoking are on the decline, fast food consumption has gone up.

The number of students who consume soda three times a week increased to 25.5 percent, a 1.2 percent increase compared to last year.

Those who enjoy calorie-heavy food three times a week accounted for 13.1 percent this year, a 1.6 percent increase from last year.

The researchers used hamburgers, pizza and fried chicken as examples in the survey.

The rate of those who skip breakfast more than five times a week rose to 26.4 percent from 24.8 percent last year.

BY PARK EUN-JEE [ejpark@joongang.co.kr]