https://www.snopes.com/fact-check/obama-deported-more-people/
Until recent years, most people caught illegally crossing the southern border were simply bused back into Mexico in what officials called "voluntary returns," but which critics derisively termed "catch and release." Those removals, which during the 1990s reached more 1 million a year, were not counted in Immigration and Customs Enforcement's deportation statistics.
Now, the vast majority of border crossers who are apprehended get fingerprinted and formally deported. The change began during the George W. Bush administration and accelerated under Obama. The policy stemmed in part from a desire to ensure that people who had crossed into the country illegally would have formal charges on their records.