Another surge of child immigrants are expected to descend upon the southern U.S. border over the next few months, with the most recent migration data predicting that 39,000 unaccompanied children will attempt to cross into the U.S. from Mexico, a 40-percent decrease from 2014 but still one of the highest projected surges on record.

The projected flow comes from a report released this week by the Migration Policy Institute, which based its numbers on the assumption that current immigration trends from the first five months of the fiscal year will continue.

Since the beginning of the 2015 fiscal year in October, 15,647 minors and 13,911 families have been detained, according to the Houston Chronicle. Two-thousand fourteen saw a record number 69,000 child migrants apprehended along the border, which eventually contributed to a "crashed system," Monique R. Grame, deputy patrol agent in charge of the McAllen Border Patrol station, told the Chronicle.

As a result of the strained and overcrowded system, federal immigration officers ended up releasing an additional 30,000 illegal immigrants with criminal records into the U.S. last year. Additionally, some human rights groups have raised concerns over possible mistreatment of immigrant families and unaccompanied children.

Border agents are now gearing up for the historically busy spring and summer months, and while they say they are much better prepared than last year, Grame said estimating how many immigrants will attempt to cross is still "a guessing game."

"Come early June, we'll have a pretty good sense of how busy it'll be," Grame told the Chronicle.

In response to last year's crisis, additional enforcement agents have been dispatched to the border, new detention facilities have been constructed, and policies have been improved to better accommodate unaccompanied children, said Gil Kerlikowske, head of U.S. Customs and Border Protection, according to The Hill. Other measures implemented to slow immigration include an international media campaign, an increase in the speed of deportation hearings, and supplemental funding for border agencies.

President Barack Obama also plans to send $1 billion in aid to Guatemala, Honduras and El Salvador to help fight the corruption and poverty that so often encourages immigrants to seek shelter in the United States, according to The Hill.

While these measures likely contributed to the decreased immigration numbers for 2015, Kevin Appleby, director of migration policy at the U.S. Conference of Catholic Bishops, told The Hill that the lower projections may have more to do with Mexico's efforts to stop unaccompanied children before they even reach the U.S. border.

"The fact that the numbers are lower is not because the administration has had an effective PR campaign or conditions in those countries have improved. We've exported the enforcement," Appleby said. "They're pulling kids off the trains; they're stopping them at the Mexico-Guatemala border. ... So there's still a violation of international law there."

Deputy director of the Migration Policy Institute, Marc Rosenblum, agreed, saying the major reason numbers have fallen is that not only has Mexico increased deportations of children at its southern border, but Mexico and Central American Countries have been conducting public education campaigns discouraging illegal immigration.