Professor Williamson is a long-term smoker. Since it was recently announced that smoking will be banned on campus, he has decided to quit. According to the Centers for Disease Control, what is the likelihood that Professor Williamson will have achieved sustained abstinence at the end of a year?

2.3% is the correct answer.

Thousands of people start smoking cigarettes every day in the Unites States, and about 70% of long term smokers want to quit smoking. However, according to the Centers for Disease Control and Prevention, the likelihood that professor Williamson will have achieved sustained abstinence by the end of the year is only 2.3%.