But just last week, the U.S. Centers for Disease Control and Prevention said that the United States won't meet the Healthy People 2010 objective of reducing the adult smoking rate to 12 percent or less.

That means that continued high levels of smoking-related health problems, deaths and lost productivity will continue to plague the nation for years to come.

"It's an enormously important time to help people make that decision to try to quit," said Thomas J. Glynn, director of cancer science and trends at the American Cancer Society.

And there's no better time to make that effort than Thursday, the 33rd annual Great American Smokeout, when the cancer society will ask smokers to try and dump the habit.

In the past year, 40 percent of the 43.4 million Americans who smoke tried to quit for at least one day. The Great American Smokeout is designed to encourage people to make a long-term plan to quit for good.

"A journey of 1,000 miles begins with a single step, and your single step begins on the day of the Great American Smokeout," Glynn said. "But then you need to follow through to stay stopped. And if you fall down, get right back up again and try again."

Quitting smoking can be difficult, Glynn acknowledged. "I think people have to look at it as a process, and the Great American Smokeout is designed to help people begin that process," he said.

There are other timely reasons to quit smoking, Glynn said, including the current economic climate. "Ignoring the health benefits, it's a great way to save money. The average smoker spends about $1,500 on cigarettes alone, let alone the increased health-care costs they have and the time lost at work. If you are looking to save money, this is priority one," he said.

Smoking is the single largest preventable cause of disease and premature death in the United States. Each year, it causes 443,000 premature deaths, including 38,000 deaths among nonsmokers from secondhand smoke. Half the people who continue to smoke will die from smoking-related diseases, according to the American Cancer Society.

According to the cancer society, there are many good reasons to quit -- and many benefits when you do:

• 20 minutes after quitting, your heart rate and blood pressure drop.
• 12 hours after quitting, carbon monoxide levels in your blood drop to normal.
• two weeks to three months after quitting, circulation improves and lung function increases.
• one to nine months after quitting, coughing and shortness of breath decrease and lung function improves.
• one year after quitting, the risk of heart disease is cut in half.
• five years after quitting, the risk of stroke is reduced.
• 10 years after quitting, the risk of dying from lung cancer is cut in half, and the risk of cancer of the mouth, throat, esophagus, bladder, cervix and pancreas decrease.
• 15 years after quitting, the risk of heart disease is the same as for non-smokers.

Dr. Jordan S. Josephson, director of the New York Nasal and Sinus Center, said the decision to stop smoking has to "come from the heart."

"A lot of people say they want to stop smoking, but truly down deep they are just not ready," he said. "But once you are ready, cold turkey seems to be the best way. Most patients just throw it in the can and they are done with it."

New York lawyer Robert Fastner is a patient of Josephson's who quit three years ago.

"I never thought it would happen," Fastner said. "Nobody who knew me ever thought it would happen. I never thought I had a shot at quitting."

Nearing 50, Fastner noticed he had developed wheezing, chronic colds and sinus infections. "It was almost like you need to quit, but you can't get yourself to do the act. I put in my head -- 'You will not turn 50 and still be smoking,' " he said.

One day he just quit. "Once I actually did it, I never looked back," Fastner said.

More information

For more on quitting smoking, visit the American Cancer Society.