ST. LOUIS (AP) — Authorities say there has been a sharp decline in the manufacture of methamphetamine in several Midwestern states that have had the most trouble with the drug, but it remains as popular as ever due to an influx of cheap Mexican imports.

Laws restricting the sale of an ingredient found in many cold medicines and key to making meth seem to have had their intended effect. The Drug Enforcement Administration doesn’t provide partial-year data on meth lab seizures, but drug fighters in several states that generally register the most meth lab busts say they’ve seen a startling decline.

Missouri is on pace for 40 percent fewer meth lab seizures this year, while Oklahoma’s are down 33 percent and Tennessee’s are down 48 percent.