Where are you getting this crap?
1. Your numbers are off, because the percentage is of adults only.
2. 400,000 die each year. The percentage of smokers who will die prematurely at some point because of smoking is over 50% (I don't recall the exact percentage but it's high).
Citation?
And what do you consider prematurely? 50? 60? 75?
I've never heard that it was adults. I've heard percentage of population.