Yeah you kind of seem to be jumping all over the place steve
The truth is that the smoking rate has declined due to a complicated number of factors. Less people are initiating smoking to begin with (youth smoking rates have been down for years), combined with more people quitting and more people switching to safer alternatives.
People have been attempting to quit in greater numbers, so at any given time, if you ask someone who previously smoked if they still do, there is a possibility that they will say "no" because they recently quit. That does not mean they will stay quit, but that will affect the final tally of current smokers.
Also, while many of us are switching to e-cigarettes (yay for us!), there is also an increasing number of people using NRTs long term in an effort to keep from smoking.
In places where you see a sudden spike in cigarette prices due to taxes, they have not shown any statistically significant decline in smoking rates. That does not mean that no one is quitting due to the higher taxes, it just means that the number who quit due to higher taxes is not high enough to affect the statistics in any meaningful way. In other words, higher taxes do not lead to less smoking overall. (In my personal experience, higher smoking taxes lead to more people complaining about taxes, and more people saying they need to quit, but not to more actual quitting).
There is no single donkey we can pin the tail on here. Yes, e-cigarettes are affecting smoking rates, but many other things are as well. Only time will tell how much of a dent e-cigs can really make in smoking rates. Statistically we need another 10 years or so to be sure (so let's hope they remain legal for that time!).