You could do better than a reference that lies about the contents of its citations. For example, there is no evidence that "over 50% of American adults over the age of 16 were functionally illiterate." The actual number is 14%, if I'm taking the cited source's statistic of "below basic prose literacy" as the definition of "functionally illiterate."

Actually, upon reading the whole article, this feels a lot more like the same millennium-old whining "kids aren't appreciating the same classics I did and therefore they're stupid idiots." Kids these days read and write a lot--text messaging, twitter, facebook, social media.

If you want to convince someone that it really is the case that people are getting dumber, you need to find references that don't read like the same age-old complaints: you need to show that it's dumber on an objective measure of intelligence, not "they don't show appreciation for the classics," which is what you usually find instead.