(AP) — Figures obtained by The Associated Press show that methamphetamine lab seizures and arrests declined nationwide in 2012, but the illicit and dangerous drug continues to hit hardest in the nation’s heartland.

The Drug Enforcement Administration provided statistics to AP showing 12,694 meth lab incidents in 2012, down 5.5 percent from 2011. Experts say it’s too early to know why the numbers dropped, and some say preliminary 2013 numbers are on the rise. Still, it was the second straight year of decline.

Missouri, the leader in meth lab incidents every year but one since 2003, again topped the list, followed by Tennessee, Indiana, Kentucky and Illinois. The top 16 states for meth lab incidents were all in Middle America or the South.