CDC, CDC Foundation, and Truth Initiative analyzed retail scanner data to assess trends in unit sales of e-cigarettes in the United States by product and flavor type.
Romeh, F., et al. (2020). E-cigarette Unit Sales, by Product and Flavor Type - United States, 2014-2020. Morbidity and Mortality Weekly Report, 69(37): 1313-1318. https://www.cdc.gov/mmwr/volumes/69/wr/mm6937e2.htm?s_cid=mm6937e2_w