But not the one's you are thinking about
DoD schools may have a higher percentage of doctors, lawyers, and engineers than your avg working class school district because all significant military bases have medical and legal facilities. Anecdotally, none of my friends parents were doctors, lawyers, or engineers growing up. And I can't think of any parents with those professions from my youth. (Contractor was the wealthy kid's dad's job in my area). The lawyers and doctors I know, i know through the military. (I think civilians typically think of the military as a bunch of privates running around being told what to do).
But that's not nearly as interesting as the *shifts* in the graph. One thing that comes to mind is the Irish —> Latino demographic shift in the laboring class. Another is the ongoing advent of an age of electronic communication, which is creating a "post-literate society," as some say.
Also, what's the value of literacy? We know that totalitarian regimes will institute literacy programs because it's easier to propagandize to the literate. And most people throughout history, including Socrates, couldn't read, relying instead on orality for communication, not literacy. Moreover, of our curriculum seems to stem from the post-WWII need for technicians to make stuff go BOOM bigger and ZOOM faster, which is why math and reading are so heavily prioritized. In other words, we have no idea what we're doing or why we're doing it. I hope that this larger, national system breaks down so we can have more experiments in how to teach/learn. I would never send my children through the school system to which I was subjected.