Year Percent of total labor force (Units) 1980 0.313 1981 0.365 1982 0.670 1983 1.022 1984 1.254 1985 0.906 1986 0.656 1987 0.441 1988 0.636 1989 1.658 1990 2.594 1991 2.925 1992 4.665 1993 5.764 1994 5.776 1995 5.250 1996 4.153 1997 4.204 1998 3.314 1999 2.489 2000 2.633 2001 2.791 2002 3.515 2003 3.525 2004 3.417 2005 2.883 2006 3.200 2007 2.492 2008 3.325 2009 8.008 2010 8.317 2011 7.700 2012 6.617 2013 5.833 2014 5.417 2015 4.500 2016 3.342 2017 3.283 2018 3.100 2019 3.925 2020 6.433 2021 6.017 2022 3.750 2023 3.383 2024 3.838 2025 4.089 2026 4.101 2027 4.065 2028 4.021 2029 4.000