"Economic analysis can be an important tool for policy evaluation, although the limited information available on drug-related public expenditure in Europe represents a major obstacle and makes comparison between countries difficult. For the 16 countries that have produced estimates since 2002, drug-related public expenditure ranges from 0.01% to 0.5% of their gross domestic product (GDP). From the information available, it appears that the largest share of drug-related public expenditure is allocated to drug supply reduction activities (Figure 4.4).
"Public expenditure on supply reduction includes, among other things, expenditure on drug-law offenders in prisons. The EMCDDA calculated a range of estimates, where the low estimate considers only those prisoners who have been sentenced for a drug-law offence and the high estimate also includes pre-trial prisoners who may be sentenced for a drug-law offence. Applying these criteria, European countries spent an estimated 0.03% of GDP, or EUR 3.7 billion, on drug-law offenders in prison in 2010. Including pre-trial prisoners, the estimate rises to 0.05% of GDP or EUR 5.9 billion."


European Monitoring Centre on Drugs and Drug Addiction, "European Drug Report 2014: Trends and Developments" (Lisbon, Portugal: EMCDDA, 2014), p. 70.………