"The estimated number of injecting drug users in Norway was also reported prior to the revision, using the mortality multiplier method. This method divides the number of drug-related deaths by the likelihood of dying of a drug-related diagnosis in the population of injectors in the 15–64 age group. First, an estimate of the number of recreational users was subtracted from the nominator because they are less likely to have injected the substance that caused the death. The probability of dying of drug-related causes among injecting drug users has been set to 2.03 per 100 person-years, based on cohort studies among such users.

"The estimate for injecting drug users in 2012 was 8,400 persons, with a sensitivity interval of 7,200–10,100. Figure 7 shows a stable trend in the number of injecting drug users since 2004, with a possible decline since 2008. With a growing population of 15–64-year-olds, however, the possible decrease in numbers is shown as a decline in the proportion of injecting drug users per 1,000 capita. Based on the method used , the decline was 15 per cent from 2008 to 2012; from 3.0 to 2.5 injecting drug user per 1,000 capita."

Source

Drug Situation in Norway 2014, Norwegian Institute for Alcohol and Drug Research (SIRUS)/EMCDDA. Statistics 2015. ISBN: 978-82-7171-422-2. Available at www.fhi.no/en
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