My sources in law enforcement (I am an medically-retired cop) tell me that it's more like 80+% is brewed in the county where it's getting sold. They seldom intercept shipments of meth in the same way they intercept pot, smack, or coke.
Yes, it is "brewed" here, but in the "superlabs," which are mainly run by illegal aliens, and their ingredients come up from Mexico, according to a number of stories I've read.
I suppose my point is that I have to question the sincerity of politicians who on the one hand, pass all kinds of restrictions on the sale of cold/allergy medications, while on the other hand, allow their states to continue to hand out driver's licenses to illegal aliens.
That's exactly what is going on here in Oregon. The legislature actually passed a law requiring a prescription for Sudafed, while the Democrats in the state Senate are blocking the implementation of the Real ID Act.