On June 17,2013, the Associated Press reported that according to the report by the Centers for Disease Control and Prevention (CDC), the smoking rates for adults have keep declining in the past decades, "last year's decrease - down to 18% - ends a smoking rate stall that hovered at 20% to 21% for more than seven years, then froze at about 19% in 2010 and 2011."

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"If you break it down by race and ethnicity, there are differences as well," said Dr. Richard Besser, the ABC News' Chief Health and Medical Editor. "Smoking among Hispanic adults is 12 percent.  Non-Hispanic white adults are at 20 and a-half percent.  And non-Hispanic blacks is at 18 percent."

Take a look back in the history, in 1997, 25 percent of adults smoked, and this year, there were only 18 percent of adults smoked. "The exciting thing about that is that the rates for smoking had leveled off to about 20 percent.  And it held there through the mid-2000s," said Besser.

Data from the Centers for Disease Control and Prevention displays that in U.S.A., smoking is the main cause of preventable illness and death in the USA, accounting for one in five deaths and direct medical costs ranging from $50 billion-$73 billion per year. According to the DCD reports, it causes more than 80% of all lung cancer deaths and coronary heart disease, the leading cause of death in the country.

So far, no data have clearly showed what causes the smoking rate to decline. "Historically, rising taxes on tobacco products, smoking restrictions and mass media and school-based educational campaigns have helped push down the smoking rate," said Joshua Yang, a tobacco control researcher at the University of California-San Francisco.