The number of migrants illegally coming across the U.S. southern border in March dropped to the lowest level in 17 years, says a leaked agency statement given to the Associated Press.

The statement is included in testimony slated for delivery on Wednesday, April 5, by Gen. John Kelly, the secretary of the Department of Homeland Security. Typically, routine testimony is provided early to the legislators so they can prepare questions for the witness, but it is rarely leaked.

According to the Associated Press:

Secretary John Kelly said the steep decline in arrests is “no accident” and credited President Donald Trump’s approach to illegal immigration… In his testimony for the Senate Homeland Security and Governmental Affairs Committee, Kelly said fewer than 12,500 people were caught crossing the border illegally last [in March]. That compares with more than 43,000 in December. Kelly told lawmakers that the number of [Central American] families and children traveling alone — groups that accounted for hundreds of thousands of illegal border crossers in recent years — also declined steeply. Last month fewer than 1,000 children were caught at the border and fewer than 1,100 people traveling as families were found. In recent years most of the families and children traveling alone have been from Honduras, El Salvador and Guatemala.

Another report on Tuesday said the data showed a 67 percent drop in migrants seeking to cross the border.

David V. Aguilar, former U.S. Border Patrol and acting Customs and Border Protection commissioner, told the Senate Homeland Security Committee that March 2017 figures he reviewed indicate illegal border crossings are down 67 percent [compared to March 2016] …. “It’s actually up to 67 percent drop compared to last year,” Aguilar told the Senate committee.

During his eight-year tenure, former President Barack Obama reduced border barriers and allowed at least 300,000 migrants from Central America to cross the border and get temporary residency, plus work permits and access to Americans’ schools. That wave of migrants helped solidify public opposition to immigration, aided Donald Trump’s presidential campaign and helped cause many extra crimes in the United States.

However, the flow of new illegal immigrants is only a small part of the nation’s immigrant-labor oversupply.

Currently, at least 11 million illegal immigrants are living in the United States, of which at least 8 million hold jobs. Many of the recent illegal immigrants arrive legally as tourists or workers but fail to leave when their visas expire. In 2015, for example, almost 500,000 people overstayed their visas and remained for some time as illegal immigrants.

Also, the federal government annually invites 1 million people to legally immigrate to the United States, and provides work permits to a shifting population of up to 1.45 million salary-cutting white-collar guest-workers, plus at least 200,000 blue-collar contract-workers. The immigrants and contract workers compete for jobs sought by the 4 million young Americans who join the workforce each year.

Overall, the huge inflow of migrants, both legal and illegal, help lower Americans’ salaries and wages by roughly $500 billion per year. In turn, that money is scooped up by employers and Wall Street investors as higher profits.

President Trump has promised to toughen border security by building a barrier along most of the border, and he has already directed border officers to end Obama’s “catch and release” policy. He has also rejuvenated repatriation policies and has promised to curb business’ use of temporary contract workers in place of Americans.