The RAND paper looks at the past 45 years of trends in income (e.g. wages) for people across percentiles (10th, 50th, 90th, etc.) and asks what would have happened if the bottom 90% of people saw their income rise at the same rate as economic growth, or growth in the gross domestic product. The paper finds that, had incomes grown for the bottom 90% the same as they did during the 1950s and 1960s — roughly aligning with growth in per capita national income and GDP — workers would have had an additional $47 trillion in income.
Source : https://www.wvgazettemail.com/opinion/op_ed_commentaries/boettner-sword-workers-in-wv-make-less-by-design-opinion/article_ac69704d-5395-57a7-a097-2e71e0707f8f.html