In 1971, a Harris survey asked "In general, to what extent do you feel blacks are discriminated against in this country--do you feel they are discriminated against a great deal, somewhat, only a little, or not at all?" In 1997 and 1999, ABC News Polls asked an almost identical question: "Do you think blacks are discriminated against in this society a lot, somewhat, a little, or not at all?" The results:
1971 1997 1999
A lot/great deal 26% 22% 26%
Somewhat 37% 49% 43%
Little 19% 20% 19%
Not at all 15% 8% 11%
On the average, people saw more discrimination in the 1990s than in 1971, mostly because of a decline in the percent choosing "not at all" (the differences are statistically significant). As far as I can tell, the original data are available only for 1997: in that year, the percents among non-Hispanic whites were 17, 53, 21, and 9, and among blacks were 44, 44, 9, and 3. Given the relative shares of blacks and whites in the population, it's safe to say that whites saw more discrimination against blacks in the 1990s than they did in 1970.
I've had several posts on this general topic (see the list at the end of this post). Although there are a reasonable number of repeated questions, none of them are repeated regularly over a long period of time. But they all seem to point in the same direction, with one possible exception: whites perceive more discrimination against blacks (and less against whites) than they used to. The possible exception is this one. I have a hypothesis about that, which I hope to check in the next few weeks.