As union membership has declined, income inequality has grown: Union membership and share of income going to the top 10%, 1917–2019
| Year | Union membership | Share of income going to the top 10% |
|---|---|---|
| 1917 | 11.0% | 45.2% |
| 1918 | 12.1% | 44.2% |
| 1919 | 14.3% | 46.1% |
| 1920 | 17.5% | 44.3% |
| 1921 | 17.6% | 47.6% |
| 1922 | 14.0% | 46.3% |
| 1923 | 11.7% | 43.9% |
| 1924 | 11.3% | 45.9% |
| 1925 | 11.0% | 47.4% |
| 1926 | 10.7% | 47.8% |
| 1927 | 10.6% | 47.3% |
| 1928 | 10.4% | 48.4% |
| 1929 | 10.1% | 47.1% |
| 1930 | 10.7% | 46.5% |
| 1931 | 11.2% | 46.5% |
| 1932 | 11.3% | 48.5% |
| 1933 | 9.5% | 48.2% |
| 1934 | 9.8% | 49.2% |
| 1935 | 10.8% | 48.3% |
| 1936 | 11.1% | 48.6% |
| 1937 | 18.6% | 47.7% |
| 1938 | 23.9% | 47.3% |
| 1939 | 24.8% | 48.8% |
| 1940 | 23.5% | 49.2% |
| 1941 | 25.4% | 47.2% |
| 1942 | 24.2% | 42.9% |
| 1943 | 30.1% | 39.4% |
| 1944 | 32.5% | 36.6% |
| 1945 | 33.4% | 35.6% |
| 1946 | 31.9% | 37.3% |
| 1947 | 31.1% | 37.2% |
| 1948 | 30.5% | 39.0% |
| 1949 | 29.6% | 38.5% |
| 1950 | 30.0% | 39.2% |
| 1951 | 32.4% | 38.0% |
| 1952 | 31.5% | 36.8% |
| 1953 | 33.2% | 35.8% |
| 1954 | 32.7% | 36.1% |
| 1955 | 32.9% | 36.9% |
| 1956 | 33.2% | 35.9% |
| 1957 | 32.0% | 35.8% |
| 1958 | 31.1% | 35.6% |
| 1959 | 31.6% | 36.1% |
| 1960 | 30.7% | 35.6% |
| 1961 | 28.7% | 35.7% |
| 1962 | 29.1% | 36.3% |
| 1963 | 28.5% | 36.7% |
| 1964 | 28.5% | 37.1% |
| 1965 | 28.6% | 36.7% |
| 1966 | 28.7% | 36.4% |
| 1967 | 28.6% | 35.5% |
| 1968 | 28.7% | 35.7% |
| 1969 | 28.3% | 34.4% |
| 1970 | 27.9% | 33.8% |
| 1971 | 27.4% | 34.3% |
| 1972 | 27.5% | 34.6% |
| 1973 | 27.1% | 34.9% |
| 1974 | 26.5% | 34.0% |
| 1975 | 25.7% | 34.3% |
| 1976 | 25.7% | 34.2% |
| 1977 | 25.2% | 34.6% |
| 1978 | 24.7% | 34.4% |
| 1979 | 25.4% | 34.7% |
| 1980 | 23.6% | 34.2% |
| 1981 | 22.3% | 34.6% |
| 1982 | 21.6% | 34.8% |
| 1983 | 21.4% | 35.4% |
| 1984 | 20.5% | 36.7% |
| 1985 | 19.0% | 36.7% |
| 1986 | 18.5% | 36.4% |
| 1987 | 17.9% | 37.4% |
| 1988 | 17.6% | 39.1% |
| 1989 | 17.2% | 38.7% |
| 1990 | 16.7% | 38.6% |
| 1991 | 16.2% | 38.4% |
| 1992 | 16.2% | 39.5% |
| 1993 | 16.2% | 39.1% |
| 1994 | 16.1% | 39.2% |
| 1995 | 15.3% | 40.0% |
| 1996 | 14.9% | 40.9% |
| 1997 | 14.7% | 41.6% |
| 1998 | 14.2% | 42.0% |
| 1999 | 13.9% | 42.3% |
| 2000 | 13.5% | 42.9% |
| 2001 | 13.5% | 42.0% |
| 2002 | 13.3% | 41.6% |
| 2003 | 12.9% | 41.7% |
| 2004 | 12.5% | 42.4% |
| 2005 | 12.5% | 43.4% |
| 2006 | 12.0% | 44.2% |
| 2007 | 12.1% | 44.2% |
| 2008 | 12.4% | 43.8% |
| 2009 | 12.3% | 42.6% |
| 2010 | 11.9% | 43.9% |
| 2011 | 11.8% | 44.5% |
| 2012 | 11.2% | 45.6% |
| 2013 | 11.2% | 45.1% |
| 2014 | 11.1% | 45.7% |
| 2015 | 11.1% | 45.7% |
| 2016 | 10.7% | 45.4% |
| 2017 | 10.7% | 45.4% |
| 2018 | 10.5% | 45.6% |
| 2019 | 10.3% | 45.5% |
Sources: Data on union density follows the composite series found in Historical Statistics of the United States, updated to 2019 from unionstats.com. Income inequality (share of income to top 10%) data is from the World Inequality database.