Year Percent of total labor force 1984 1.62 1985 2.22 1986 2.75 1987 2.64 1988 2.89 1989 2.86 1990 2.59 1991 2.67 1992 2.79 1993 2.83 1994 4.47 1995 7.42 1996 4.998 1997 4.77 1998 5.46 1999 6.36 2000 6.08 2001 8.1 2002 9.06 2003 9.5 2004 9.86 2005 11.24 2006 10.28 2007 9.11 2008 8.39 2009 7.87 2010 7.14 2011 6.56 2012 6.14 2013 6.25 2014 5.94 2015 6.18 2016 5.61 2017 5.5 2018 5.34 2019 5.2 2020 5.01 2021 5 2022 5 2023 5 2024 5