I would think I am category 4. Acknowledges its existence ( and has family members with it), but wonder why the increase. Has the existence gone up? Or is the existence the same, but more people are being diagnosed? Or has the criteria changed? I ponder the same thing about other things, too, like peanut allergies, etc.
The second thing that jumped out at me is the huge statistical difference between white kids (much higher rates) and black kids (much lower rates).
The combination of these two -- coupled with my own experience in dealing with friends who have young children -- tells me that there's a lot of monkeying around with the numbers and (in some cases) even outright fraud going on. In a state like New Jersey you have a situation where a lot of parties -- parents, medical professionals, the pharmaceutical industry, and school districts, for example -- have a vested interest in diagnosing as many kids with "disorders" as humanly possible. In New Jersey, a kid who is diagnosed with this kind of "disorder" is provided special instructional arrangements in school (maybe even including one-on-one tutoring). And the local school district qualifies for all kinds of additional state aid to deal with all these "disordered" kids.
This is why I suspect the explosion in ASD is largely a suburban phenomenon. For many parents who have ambitions for their kids that border on pathological, ASD is a perfect "disorder" because it's the type of disorder that can get little Freddie plenty of extra medical and educational attention ... but will never be diagnosed as a disorder dangerous enough to have him institutionalized.