One in five high school going students in the U. S. has still not stopped smoking, and the rate of decline in smoking has seen a downward trend, according to a new report that released on Thursday from the Centers for Disease Control and Prevention.

Smoking rates amongst high school students became snail-like noticeably from the late 1990s through the early 2000s. But those rates of drop decreased more steadily from the early to late 2000s.

The CDC assessed figures from the National Youth Risk Behavior Survey of high school students studying in public and private schools in all states and the District of Columbia.

The proportion of students who said that they were still smoking cigarettes (defined as smoking a cigarette for no less than one day of the 30 before the survey) went from
27.5% in 1991 to 36.4% in 1997, then went downward to 21.9% in 2003. In 2009 that figure was 19.5%, which was a representation of sluggish drop.

The fraction of students who ever tried smoking even one cigarette (even taking one or two puffs represented trying a cigarette) stayed stable from 1991 to 1999.

That group then saw a big plunge as rates went from 70.4% in 1999 to 58.4% in the year 2003. A new gradual drop was seen after that, to 46.3% in 2009.