() For years, a rise in border trafficking of illegal drugs, including fentanyl, led to one of the most dangerous epidemics in U.S. history, but new data suggests the worst may be behind.

Last year, the U.S. Border Patrol seized more than 1,700 pounds of fentanyl per month compared to only 746 pounds a month so far this year. That’s a drop of more than one half, if the pace holds.

U.S. seizures have decreased by 30% at the border compared with the same period last year, the Washington Post reported. A source in Mexico tells the drop in fentanyl seizures indicates the U.S. government has been successful in putting pressure on its neighbor to the south to crack down on fentanyl production.

The Trump administration has made fentanyl trafficking a national security issue and has threatened Mexico with tariffs. Mexican President Claudia Sheinbaum responded by deploying 10,000 troops to her country’s northern border.

The two countries are also cooperating in the field. U.S. authorities worked alongside Mexican federal agencies to dismantle three large-scale synthetic drug production labs in Sinaloa, Mexico, a stronghold for the Sinaloa Cartel.

The cooperation adds new pressure on cartels to produce less of the synthetic opioid so that they can avoid the attention of the U.S. government.

U.S. Rep. Dan Crenshaw, R-Texas, recently praised Mexico for busting a fentanyl super lab that was producing 2 tons of the drug each week. The lab was dismantled, and authorities seized $80 million in product.

Another factor in the drop in fentanyl seizures: The Sinaloa Cartel is involved in a civil war between two factions.

Even with the tide turning at the border, fentanyl remains cheap and widely available in the United States.