Border Patrol agents encountered nearly 7,000 people at the border in 2018 who were previously convicted on criminal offenses in the U.S. or abroad, according to newly released government data.

Exactly 6,698 people of the 683,178 people who Border Patrol made contact with from Oct. 1, 2017, through Sept. 30, 2018, were flagged in federal background check systems for having been convicted of a serious crime.

Approximately 1 percent of all apprehended last year, which includes those who were turned away at ports of entry, were known criminals.

[Related: February marked 12-year-high for illegal immigration: 76,000 encountered at southern border]

In 2017, more than 8,500 of the 526,000 people encountered were known convicted criminals, data shows.

That figure was down from 12,800 arrests of known criminal in 2016. Approximately 690,000 immigrants tried to illegally cross or were turned back at ports of entry that year.

Last year saw a surge in Central American families arriving at the southern border and fewer Mexican adults compared to historical trends.

[Also read: John Kelly: Wall along the entire border a 'waste of money']