But more accurate government statistics imply that the real incomes of those at the middle of the income distribution have increased about 50% since 1980. And a more appropriate adjustment for changes in the cost of living implies a substantially greater gain.
比如，人们常说，过去几十年来平均家庭收入增长十分缓慢（甚至停滞不前）。一些美国人口普查数字似乎支持这一结论。但更准确的政府数据表明，位于收入分布中端的家庭的实际收入自1980年以来增加了大约50%。如果针对生活成本进行更合适的调整，那么中产阶级的的收益还会大大提高。