2.5 metric tons - and those are just the bonus shipments- almost like the various smugglers on commercial flights - its not the real method they rely on - but it is the cheapest
my guess is the mexican cartels bringing it over / under the border is #3
I've seen some of the weight that comes in on cargo flights, packed in with fresh seafood etc - everyday, multiple flights - with each flight carrying 3-4x what a sub or one of various boats carry
now the numbers getting in using cargo containers on freight ships