Fig. 5

Estimated incidence of methamphetamine abuse using data for outpatient rehabilitants in Cape Town. Our estimated incidence of methamphetamine abuse, evaluated using the initiation function \(\lambda S\), is observed to be decreasing sharply from the first half of the year 2000 down until the second half of the year 2002. It then suddenly increases from about 9 % in the year 2003 reaching an estimated incidence of 13 % in the second half of 2008, after which it steadily decreases until the first half of the year 2013