Figure 3.

The prevalence of current e-cigarette/ENDS use among adult former smokers, online and traditional survey estimates, * 2010–2016. * The estimates from online surveys are indicated by an X, and the estimates from traditional surveys are indicated by a circle. The legend adopts the format “author’s name, publication year (survey name and year(s)),” and the names of all online surveys are omitted. For surveys that collected data over a two-year period, we plotted the estimates in the mid-period. ** Authors’ estimate one is measured by daily/nondaily ENDS use, and authors’ estimate two is measured by past-30-day ENDS use.