A number of different factors have led to a decline in smoking rates among adults.

Smoking rates among adults have declined rapidly over the past year.

According to a report from ABC News, the CDC has reported that the smoking rate among adults fell to a mere 15% last year, down from approximately 17% in 2014, marking the biggest one year decline in over 20 years.

The smoking rate among adults has been falling for decades, but usually only approximately one percentage point or less per year. ABC News reported that the last time there was a drop nearly as steep was from 1992-1993, when it fell 1.5%.

There are a number of different speculations as to why the smoking rate fell so quickly in the last year, and it is unclear whether it will continue falling at this rate. ABC News pointed out that the smoking rate’s gradual decline has been in sync with the increased public understanding that smoking has harmful side effects.

ABC News reported that experts are attributing the recent smoking rate declines to the increase in anti-smoking advertising campaigns, cigarette taxes and smoking bans.

Along with the numerous anti-smoking efforts, the increased marketing of electronic cigarettes and their growing popularity may also be playing a role in smoking declines, ABC News speculated. But there is also the possibility that the increase in e-cigarette use may contribute to an increase in smoking in years to come. While e-cigarettes are a potentially useful tool to help smokers quit, some experts fear that they may be a new way for people to develop a nicotine addiction. However, despite these fears, many experts remain optimistic.