1. Over the past few years, blacks have gotten less than they deserve. 2. Irish, Italian, Jewish, and many other minorities overcame prejudice and worked their way up. Blacks should do the same without any special favors. 3. It's really a matter of some people not trying hard enough; if blacks would only try harder they could be just as well off as whites. 4. Generations of slavery and discrimination have created conditions that make it difficult for blacks to work their way out of the lower class.
This scale certainly measures something of interest, but "resentment" doesn't seem like the right term. Resentment isn't a belief that everyone can make it if they try--it's a belief that someone else is getting an unfair advantage. I looked for questions that seemed to measure racial resentment and found one: "For each of the following groups, please tell me whether you feel that they are receiving too many special advantages, receiving fair treatment, or are being discriminated against" (with some very minor variations in wording). The figure shows changes in what people say about blacks ("African Americans" in 2008).
Oddly, the question hasn't been asked since 2008. Between 1990 and 2008, there was no clear change in the percent saying that blacks received special advantages (what I would call "resentment"), but there seems to have been a shift away from saying that they are discriminated against and towards saying that they receive fair treatment.
Another expression of racial resentment is the idea that whites are the ones who really face discrimination. The 1992 and 1997, the surveys asked about whites: both times, about 15 percent said whites got special advantages, and about 20% said they were discriminated against. Putting the figures together, "racial resentment" seems to be a minority view. "Racial complacency" is more common and may be on the rise.