DOES THE FENCE WORK -- OBJECTIVE EVIDENCE PROVES IT ALREADY HAS ?

What can we derive from this MARCH to MARCH 2000-2018 charge of know illegal crossings based on apprehensions as presented by FactCheck.org?
The Secure Fence Act was passed at the end of 2006, and 613 miles of the fence were completed by April 2009
NOTE that, with Trump's Hardline on Immigration, the arrests had fallen to under 4.25% of their 220,000 pre-fence peak amount as presented in the chart accompanying the Fact Check article.

Looking at a second chart in that presentation:

As we seen Reagan's anti-fence stance and amnesty served to enhance illegal crossings.  The Terrorist attack on 9/11 caused a drop -- by raising questions of safety in America -- and then Bush's attack on Terrorists restored confidence in safety and a resurgence of illegal entry that came to an end with the introduction of the Secure Fence Act and construction of roughly 650 miles of fence along the 2000 mile border. 
We see a further drop during the period of tough talk about undocumented immigrants who entered illegally -- trash-talk by Senator Chuck Schumer and President Barack Obama.  The drop was enhanced when Trump demonstrated he would continue the Trash-talk and back it up with more Wall or Fence and meaningful prosecutions.

That's all The Fence caused -- a drop from 1.65 MILLION to a mere 300,000.  And with it came the significance of those who overstay their LEGAL VISA -- many of whom are actually just between papers.
It happens with Fiancee VISA holders who marry within the 90-days and need to wait a year for their papers to be adjusted to full legal citizenship path status, and with those whose weddings are delayed and so carry them beyond the 90-day marriage period -- sometimes resulting in their having to exit and reenter the country as already married spouses, and other times simply waiting for the hearings to whatever that will allow them to remain within the States as their paperwork is adjusted by an understaffed and overworked Immigration and Naturalization Service. 
How understaffed and overworked? During the days of Ellis Island, immigrants could be processed in hours, now, as we see at the Mexican border, they need to wait a year just to get an appointment to have a hearing -- a year after that.