A study conducted by Kenneth Couch and Mary Daly found that the occupational distribution between blacks and white improved between 1970 and the 1990s.
由肯尼斯·靠奇（Kenneth Couch）和玛丽·戴利（Mary Daly）进行的一项研究表明，从1970到1990年代，黑人与白人的职业分布差距呈上升趋势。