Fig. 2. History of “Ever Use” of e-cigarettes in teenagers by country and period^{9,18,25–27,30,33}.

History of “ever use” of e-cigarettes in Canada, the United States, Great Britain, and the rest of Europe between 2015–2017 and 2018–2019^{9,18,25–27,30,33}. If countries reported history of past use within any of these time periods, they were included. Please note that the 2015–2017 prevalence of ever use is for the following European countries: Belgium, Finland, Germany, Ireland, Italy, the Netherlands, and Portugal²⁸. The 2018–2019 report in Europe collected data from Central and Eastern Europe, including the following countries: Poland, Lithuania, Belarus, Slovakia, and Russia¹⁸. It should be noted that while the report by Hammond et al⁹ reported a prevalence of “ever use” in the United Kingdom of 32.7% (2018), the Action and Smoking on Health Report in England²⁵ produced a significantly lower prevalence of 16.4% for the same period in Great Britain. It could be that Northern Ireland has a higher prevalence of ever use and was omitted from the report.