When President Trump addressed the nation tonight — 18 days after he forced a government shutdown over his proposed border wall — he made the case that illegal border crossings have become a crisis that threatens national security.

The big picture: There has been a surge of asylum claims and families crossing the southern border this past year, but it is no worse than other increases in recent years, according to data from U.S. Customs and Border Protection.

Expand chart Data: U.S. Customs and Border Protection; Chart: Naema Ahmed/Axios

And the border numbers are actually low compared with long-term trends. There were more than a million apprehensions a year at the southern border for most of the 1990s, compared to just under 400,000 in 2018, according to the Migration Policy Institute.

compared with long-term trends. There were more than a million apprehensions a year at the southern border for most of the 1990s, compared to just under 400,000 in 2018, according to the Migration Policy Institute. But today, far more are humanitarian migrants instead of needed migrant workers, Tamar Jacoby, president of ImmigrationWorks USA, told Axios.

Between the lines: There was an abnormally low number of migrants caught crossing the border in 2017, likely due to the uncertainty and fear sparked by the first months of Trump's presidency. Keep that in mind if Trump touts large year-over-year increases in border crossings, as the White House has to Congress.

By the numbers:

The U.S. has received a surge of asylum claims under the Trump administration. There were nine times as many asylum applications filed in 2017 than in 2009. A wall would not end immigrants' legal right to claim asylum.

claims under the Trump administration. There were nine times as many asylum applications filed in 2017 than in 2009. A wall would not end immigrants' legal right to claim asylum. Despite the threats of family separation , there were almost 32,000 more family members caught crossing the border in 2018 than in 2017, most of them from Central American countries.

, there were almost 32,000 more family members caught crossing the border in 2018 than in 2017, most of them from Central American countries. There has also been a rise in unaccompanied children crossing the border, although those numbers have not reached the highs of 2014 under the Obama administration.

crossing the border, although those numbers have not reached the highs of 2014 under the Obama administration. Smugglers have begun dropping off immigrants in remote areas of the U.S., where they overwhelm border patrol, the Washington Post's Nick Miroff reports.

dropping off immigrants in remote areas of the U.S., where they overwhelm border patrol, the Washington Post's Nick Miroff reports. But while White House press secretary Sarah Sanders claimed that nearly 4,000 people on the federal government's terror watch list were stopped by Customs and Border Protection last year, only 6 such immigrants were arrested in the first half of 2018, according to NBC News.

Background: Barack Obama faced his own border crisis in 2014, when a record number of Central American minors flooded the border. There were widespread reports of mistreatment and children in cages, and Obama considered changing a law that would allow his administration to more quickly deport immigrant children.

The impact: While the U.S. has seen migrant surges like this in the past, the agencies responsible for processing and caring for immigrants — many of whom have fled serious violence — are overwhelmed.

Detention centers are consistently at or near capacity.

Two young children have died in border patrol custody, despite the agency referring hundreds of immigrants for medical care every week, according to CBP.

There are a record number of children in the hands of the Department of Health and Human Services, and thousands living in what were supposed to be temporary tent cities.

The bottom line: The numbers aren't record-breaking, but the humanitarian crisis is real.