"On the basis of seizure data, heroin trafficking within the Americas, in particular to the United States, appears to have increased over the past decade. Quantities of heroin and morphine seized reported in the Americas rose from 4 per cent of the global total (excluding seizures made in Afghanistan) in 2008 to 9 per cent in 2018.
"Most heroin (and morphine) trafficking in the Americas continues to take place within North America, i.e., from Mexico to the United States and, to a far lesser extent, from Colombia and from Guatemala (typically via Mexico) to the United States. Based on forensic profiling, United States authorities estimated in 2017 that over 90 per cent of the heroin samples analysed originated in Mexico and 4 per cent in South America, while around 1 per cent originated in South-West Asia. This stands in stark contrast to a decade earlier (2007), when only 25 per cent was sourced from Mexico and 70 per cent was imported from South America.14"
World Drug Report 2020. Booklet Three: Drug Supply. June 2020. United Nations publication, Sales No. E.20.XI.6).