who's serving the country, anyway?

I read a blog post recently about the demographics of US military servicepeople that surprised me. Apparently , enlisted recruits in the American military are disproportionately upper and middle class. Furthermore, whites and blacks are about equally represented (with respect to the general population), while Hispanics are underrepresented. Somehow I had the impression that more of our soldiers were minorities from low-income backgrounds. I'm kind of happy to have been wrong.