A survey shows that in the first 20 months after the citywide indoor smoking ban took effect in Lexington, Ky., more than 16,400 people have given up the habit.

The UK College of Nursing researchers released their study on Dec. 11, 2006, and it shows Lexington's percentage of adult smokers has dropped by nearly one-third since the city's indoor smoking ban was implemented in April 2004.

Federal health interviews with just over 3,400 Kentuckians in six counties between 2001 and 2005 were used to determine how much adult smoking rates have changed.

Before the smoking ban, federal health surveys found that 25.7 percent of Fayette County adults smoked. In the months after the smoking ban was implemented, the figure dropped to 17.5 percent.

UK professor of nursing Ellen Hahn pushed for the smoking ban and co-authored the report. She said Fayette County's 32 percent drop in smoking is "a huge thing."