Wow. Check out this question from a 1970 DC Comics reader questionnaire:
"Black People"??? Talk about your ever lovin' snapshot in time. Thirty-seven years ago and nary a black face was seen in comics. Such a question today would seem utterly absurd, of course, but I'm wondering why DC didn't use a bit more tact and use "Civil Rights" since in 1970 that was a certainly a hot political and cultural topic.
At least Marvel was ahead of the curve back then.
Be sure to check out the best comics blog out there (from where I got this questionnaire image), Comic Coverage!