There are two ways to look at that. One is, when they start doing dual use, is that actually an exit strategy from cigarettes completely or is it a stable state? We don't have the science to suggest what it is, but we do have something to point to. As shown in a study by my colleague, Robert West, in the U.K., who I think is presenting to you, if you look at a population, you will see that before they make that attempt at quitting, often the population will have started reducing their cigarette use before they quit. So anything that can help people to reduce.... Generally, we need to study to see if it actually translates into quitting. The unanswered question with e-cigarettes is whether it becomes, as you rightly pointed out, a matter of, “I will smoke when I can, and when I can't smoke, I'll vape”.
It's a great unanswered question right now.