Year Percent of total labor force 1980 0.313 1981 0.365 1982 0.67 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 2.457 1992 4.19 1993 5.297 1994 5.315 1995 4.794 1996 3.698 1997 3.749 1998 2.86 1999 2.034 2000 2.178 2001 2.335 2002 3.076 2003 3.358 2004 3.05 2005 2.583 2006 2.875 2007 2.292 2008 2.983 2009 7.233 2010 7.558 2011 7.05 2012 6.025 2013 5.392 2014 4.958 2015 3.992 2016 3.008 2017 2.825 2018 2.742 2019 3.3 2020 3.6 2021 3.75 2022 3.75 2023 3.75 2024 3.75