More smokers in Wales are getting help to try to stop since the ban on lighting up in public places.
28% of 15-year-old girls in Wales smoke
Stop Smoking Wales, an assembly government-funded service, said there had been a 20% rise in people wanting to quit after the ban began in April.
But Tony Jewell, Wales' chief medical officer, said thousands more could still make use of the service.
He urged smokers to make giving up their top resolution in 2008 after the success enjoyed by others this year.
The ban on smoking in public places was enforced in Wales on 2 April, leading to on-the-spot fines for those who ignore it.
SMOKING IN WALES
Some 6,000 people die from smoking each year
It may account for eight in 10 deaths from lung cancer, three in four from chronic obstructive pulmonary disease, and one in five from heart disease
On average, smokers die about 10 years younger
25% of adults smoke - 27% of men and 24% of women
37% of mothers smoke at some stage in their pregnancy or the year before
28% of 15-year-old girls and 19% of 12-year-olds regularly smoke
37% of households with children contain at least one adult who smokes daily
Blaenau Gwent has the highest adult smoking rate (32%); Monmouthshire the lowest (23%)
17% in managerial and professional households smoke, 32% in manual occupations, and 48% in the never-worked and long-term unemployed group
Treating smoking costs the NHS across the UK £1.5bn a year
Source: Welsh Assembly Government
The figures show more than 25,000 smokers have contacted Stop Smoking Wales since 2004.
About 70% of smokers say they want to quit, and some half of those who go through the Stop Smoking Wales programme, offered by the National Public Health Service, succeeded in giving up for good.
Dr Jewell said: "While the number of adult smokers is falling, there are still 6,000 premature deaths each year due to smoking.
"A quarter of adults in Wales still smoke - more than the UK average - and children are taking up the habit around the age of 12."
The chief medical officer said there is no disputing the "devastating effects" of smoking on the individual or their family and friends.
Dr Jewell added: "In particular, I'd urge those who expose children to second-hand smoke to give up.
"More mothers-to-be smoke in Wales than in any other part of the UK, and over a third of households with children still contain a smoker."
The smoking ban in public places in Wales was introduced in April
He said smoking prevalence in Wales had fallen from 35% in 1978 to 25% in 2007 but believed the figure could be even lower.
"We should be aiming for an intermediate goal of 17% prevalence, as has already been achieved in Sweden and California."
Stop Smoking Wales provides a free support programme offering local weekly meetings, delivered in GP practices, health centres, schools, workplaces, libraries and leisure centres.
Julia James of Stop Smoking Wales said: "Smokers are four times more likely to stop smoking for good with help from out services than they are if they go it alone."