Cigarette smoking is directly linked to well over 400,000 deaths due to cancer, cardiovascular disease and stroke every year in the U.S. In the U. S. less than 10 per cent of the people who quit smoking for a day remain abstinent one year later. With only 2 or perhaps 3 % of smokers succeeding in there attempt to quit. With the mental withdrawls often continuing for months after the physical withdrawls have subsided. Cigarette smoking is considered among one of the most addicting of all drugs. One third to one half of occasional cigarette smokers graduate to physical dependence. There are approximately 1 billion cigarette smokers in the world today and approximately 3 million people over the world die each year from smoking related illnesses. Most tobacco-dependent persons never achieve lasting abstinence and half die prematurely of tobacco related disease. Still, major gains have been made in reducing smoking prevalence over the past three decades. Overall, smoking has dropped from 40% of the U.S. population over the age of 18 to about 24% since the mid-1970s. I hope this helps to answer your question.