(CNN) - Border Patrol arrests on the US-Mexico border continued to drop in September, marking a steady decline since the high earlier this spring when Trump administration officials struggled to stem the flow of migrants attempting to enter the US.
There were nearly 40,000 arrests on the southern border in September, which was the lowest month this fiscal year, according to a source familiar with the data.
Apprehensions along the southern border were higher in fiscal year 2019 than in any fiscal year since 2007, with slightly more than 850,000 arrests, according to Border Patrol data.
Border Patrol apprehensions, which are used as a measure of illegal crossings, are particularly important to President Donald Trump, who views them as a barometer of the situation along the southern border, according to administration officials.
Customs and Border Protection, which oversees US Border Patrol, does not comment on unofficial numbers.