According to the report hash traditionally contains more THC than marijuana. The average THC-content of all the marihuana samples together was 14,9% and that of the hash-samples19,2%. The average THC-content of nederwiet (15,5%) was significantly higher than that of the imported marihuana (5,7%). The average THC-percentage of the marihuana samples that were bought as most potent (16,9%) did not differ from that of the most popular varieties of nederwiet (15,5%). Hash derived from Dutch marihuana contained more THC (35,0%) than hash originating from foreign cannabis (16,1%). The average THC-percentage of nederwiet was lower in 2012 than in 2011 (15,5 vs. 16,5%), but this difference was not statistically significant. The THC-percentage in imported hash was significantly higher than the year before (16,1% in 2012 versus 14,3% in 2011).