Year Percent of total labor force (Units) 1980 2.017 1981 2.208 1982 2.350 1983 2.658 1984 2.708 1985 2.625 1986 2.767 1987 2.850 1988 2.517 1989 2.250 1990 2.100 1991 2.092 1992 2.150 1993 2.500 1994 2.892 1995 3.150 1996 3.367 1997 3.400 1998 4.100 1999 4.667 2000 4.733 2001 5.042 2002 5.358 2003 5.242 2004 4.733 2005 4.425 2006 4.117 2007 3.833 2008 3.983 2009 5.075 2010 5.058 2011 4.583 2012 4.325 2013 4.008 2014 3.583 2015 3.375 2016 3.108 2017 2.825 2018 2.442 2019 2.358 2020 2.783 2021 2.808 2022 2.592 2023 2.567 2024 2.500 2025 2.500 2026 2.500 2027 2.500 2028 2.500 2029 2.500