Willpower is not the only factor that determines the success of those new year's resolutions to stop smoking.
Researchers have calculated the exact role of the tax man for the first time.
Andrew Jones and Martin Forster, of York University's department of economics and related studies, have matched smokers' personal histories from the 1984 British Health and Lifestyle Survey to tax rates dating from 1920.
This has revealed the "tax elasticity", or proportionate effect of above-inflation duty increases, on the age smokers take up the habit and how long it takes before they quit.
They discovered that men were more influenced by tax increases than women and that people with higher education were less likely to take up smoking and smoked for shorter durations.
The calculations predicted a 6 per cent decrease in the number of years an average man would smoke for every 10 per cent tobacco tax increase. Women were predicted a 4.6 per cent decrease.
Such a tax rise would also increase the age of starting smoking by 1.6 per cent for men and 0.8 per cent for women.
Professor Jones explained this meant that an average smoking career of 35 years would be reduced by two years for a man, a significant effect over the estimated 12 million smokers in the United Kingdom. The National Health Service attributes a £1.7 billion bill and 120,000 deaths a year to smoking, as well as hundreds more from passive smoking.
The government is expecting £7.8 billion in tobacco tax revenue for the coming year.
Tobacco tax increased steeply around the second world war and levelled out until the 1990s, when the government committed itself to above-inflation rises as a public health policy.
This year's tobacco tax rise was set at the rate of inflation. Professor Jones suggests this may be because smokers are turning to the black market and to cheaper continental cigarettes rather than quitting.
The findings are published in the Journal of the Royal Statistical Society (Statistics in Society).