 Although 70% of smokers state their intention to quit only 3–5% are actually successful in doing so.The probabilities of death from lung cancer before age 75 in the United Kingdom are 0.2% for men who never smoked (0.4% for women), 5.5% for male former smokers (2.6% in women), 15.9% for current male smokers (9.5% for women) and 24.4% for male "heavy smokers" defined as smoking more than 5 cigarettes per day (18.5% for women).Tobacco smoke can combine with other carcinogens present within the environment in order to produce elevated degrees of lung cancer.