Irrespective of how one interprets the graph and chart, the fact remains that Trump was President from January 20th 2017 until January 20th 2021 - the 2019th, 2018th and most of the 2017th lines all fall within the time frame when he was in the White House!
Apparently Republicans only started shedding "crocodile tears" for the "suffering" of illegal immigrants after President Trump left office - where was this sudden concern from conservatives when children were deliberately separated from their parents at the border, followed by the Trump Administration's inability to reunite 100's of them with their parents due to bungled record keeping!
Biden's representatives attempted to have border facilities expanded during the 3 months prior to taking office, unfortunately the Trump Administration was still contesting the 2020 Election and saw no need to make provisions for a transition!