decline in the new millennium, it appears that progress in some areas may now be stalling.

Between 1965 and 2005, the percentage of adults who once smoked and who had quit more than doubled from 24.3 to 50.8 percent. Furthermore, the percentage of adults who had never smoked more than 100 lifetime cigarettes increased by approximately 23 percent from 1965 (44 percent) to 2005 (54 percent). Smoking initiation among adolescents and young adults has also declined since the mid-1960s. Among adolescents aged 12 to 17 years, 125.5 of every 1,000 smoked a cigarette for the first time in 1965. In 2003, 102.1 per 1,000 youths in the same age range had smoked a cigarette for the first time. The reduction in smoking initiation saved more than half a million adolescents from having a first cigarette between 1965 and 2004.

The steady decline in tobacco use since 1965 can be divided into two phases, the first running from 1965 to about 1980 and the second running from 1980 to the present. During the initial period, there was a sharp decline in smoking prevalence due to reduced initiation and increased cessation, accompanied by a modest increase in the average number of cigarettes smoked per day by smokers. However, since then, the continued decline in smoking prevalence has been accompanied by a substantial decline in cigarettes smoked per day among those who smoke. The committee believes that a substantial portion of the declines in smoking prevalence and smoking intensity over the past 25 years is attributable to tobacco control interventions, especially price increases and the emergence of a strong anti-smoking social norm.

Current trends, however, suggest that the annual rate of cessation among smokers remains fairly low, that the decline in the initiation rate may have slowed, and that overall adult prevalence may be flattening out at around 20 percent. These trends suggest that substantial and sustained efforts will be required to further reduce the prevalence of tobacco use and thereby reduce tobacco-related morbidity and mortality.

What factors are perpetuating the tobacco problem? First and foremost, tobacco products are highly addictive because they contain nicotine, one of the most addictive substances used by humans. Nicotine addiction stimulates and sustains long-term tobacco use, with all of its serious health hazards and social costs, and poses significant challenges to smoking cessation efforts at both the individual and the population levels. Although an overwhelming majority of smokers (90 percent) regret having begun to smoke, overcoming the grip of addiction and the associated withdrawal symptoms is difficult; most smokers must try quitting several times before