Perhaps Donald Trump has a valid point about Mexico’s threat to the United States, because the 2016 US National Heroin Threat Assessment notes that «Mexican traffickers have taken a larger role in the US heroin market, increasing their heroin production and pushing into eastern US markets». The report points out that 10,574 Americans died of heroin overdoses in 2014 and that the figure is rising — but there is no mention of heroin coming from Afghanistan, where, as reported in the UN Office on Drugs and Crime 2016 Opium Survey, the area under poppy cultivation increased from 183,000 to 201,000 hectares in 2015-2016, and opium production has risen by 43 %.
Source