Given the potency of the drugs and the small amounts that need to be transported, combatting illicit supply is extremely difficult, though with some success recently. U.S. Custom and Border statistics reveal that discovery of fentanyl has increased considerably in the past couple of years from essentially none in 2015 (US CBP, 2018(52]). These statistics also show a marked increase in seizures of methamphetamine (which tripled between 2012 and 2017).