How many smokers quit each year and what is the rate of reversion or
the average number of attempts before success?

Hello.

From a US Government document on quitting smoking:

"Every year 17 million Americans try to quit smoking, but only 1.3
million of these smokers are able to stay off cigarettes. That means
that  over 90% of smokers who try to quit cannot stay tobacco-free.
...
Over 90% of quit attempts fail."
http://www.smokefree.gov/pubs/FFree1.pdf


"Statistically, smokers quit an average of seven times before finally succeeding"
http://www.co.sanmateo.ca.us/vgn/images/portal/cit_609/40/29/237018317GreatAmericanSmokeout.pdf

"Most smokers want to quit smoking but find it very difficult,
attempting an average of seven times before they are successful."
source: Smokingorhealth.org
http://www.smokingorhealth.org/smokefree/facts/cessation.htm

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search strategy:
"million Americans try to quit smoking"
smoking "average of * times before"

I hope this helps.