An increase in the number of unaccompanied alien children who have come to the U.S. so far this year is a crisis that “has not been averted” and ought to cause “alarm bells” to sound off, Wisconsin Sen. Ron Johnson said during a hearing on Tuesday.

In an exchange with Department of Homeland Security Sec. Jeh Johnson at a hearing of the Senate Homeland Security and Government Affairs Committee, Sen. Johnson pointed to statistics compiled by U.S. Border Patrol which show a 10 percent increase in the number of unaccompanied alien children (UAC) apprehended in the first five months of fiscal year 2016 compared to the same time span in 2014.

That was the same year that an unprecedented wave of unaccompanied minors — largely from Central America — crossed the border. The surge was largely unanticipated by the federal government and caused a shock to the immigration agencies and to the Department of Health and Human Services, which is charged with processing UACs.

“In the first four or five months of data, alarm bells ought to be ringing,” Sen. Johnson told DHS’ chief. “The crisis has not been averted. It’s not getting better, it’s getting worse, even over 2014.”

So far this fiscal year, 23,593 UACs have been apprehended at the southern border, according to Border Patrol statistics. That’s compared to 21,431 that were apprehended by the same point in fiscal year 2014.

“It came down in 2015, but the early indications of the first four or five months of 2016 is going to be worse than 2014,” Sen. Johnson said.

Through the first five months of 2015, 12,513 alien minors were apprehended.

Johnson offered two projections of the total number of UACs that can be expected to cross the border this fiscal year. Based on the 68,541 UACs from all nations — including Central American countries and Mexico — that were apprehended and processed in 2014 and the 10 percent increase that has been observed so far this fiscal year, Johnson projected that 75,000 UACs could be apprehended.

Johnson also extrapolated based upon the seasonal spike in UAC apprehensions that normally occurs during the summer. He asserted that “with just unaccompanied children from Central America,” there has been a 49 percent increase in apprehensions in the first four months of fiscal year 2016 compared to 2014.

“[That] would imply — you can run the numbers out — about 77,000 unaccompanied children from just Central America if that would hold,” Johnson said.

DHS’ Johnson quibbled a bit with his counterpart’s projections, pointing out that while overall UAC apprehensions this fiscal year are higher than in 2014, they were lower in January and February 2016 than in the same months in 2014.

“I do think that the comparator [sic] to 2014 is imperfect in that there’s a certain trend that existed in 2014 that doesn’t exist in 2016. The numbers in January and February 2014 were considerably higher than the numbers in January and February 2016,” Johnson said.

According to Border Patrol statistics, 3,706 and 4,848 UACs were apprehended in January and February 2014, respectively. That’s compared to 3,115 and 3,113 apprehended January and February of this year, respectively.