Official UK statistics
Prevalence with the denominator attached.
Official survey estimates are handled as statistical resources, not as biomedical evidence or causal conclusions.
Comparability matters
ONS series: survey/question changes in 2018 and 2020 affect parts of the time series. SCC Vaping retains accompanying notes rather than presenting every year as directly interchangeable.
Adults
ONS e-cigarette estimates are retained with year, population group and confidence limits in the research release.
Young people
NHS England and OHID indicators are kept in a separate youth statistical layer with survey provenance.
No causal inference
A prevalence change is a descriptive observation. It is not, on its own, evidence of why use changed or what health outcome followed.