Comparison between the observed notification data among males in different age groups and model predictions of disease incidence during the period 1967–2015, based on best-fitting estimates of the risks of disease and assuming that the annual risk of infection was 10% in 1950, and that it declined by 7·5% p.a. until 1967, by 13·5% p.a. between 1967 and 1978. In the figures in the left-hand panel, the decline in the annual risk of infection (ARI) is assumed to have halved after 1978 to 6·75% p.a. In the figures in the right-hand panel, ARI is assumed to have remained unchanged after 1978. The shaded areas reflect model predictions of the proportion of disease attributable to recent infection, re-infection and reactivation. Note that, as a result of the high prevalence of infection in all the age groups considered here (see e.g. Fig. 1), none of the disease incidence is attributed to recent (primary) infection.