Year Percent of total labor force 1981 0.5 1982 0.5 1983 0.5 1984 0.5 1985 0.5 1986 0.5 1987 0.5 1988 0.5 1989 0.5 1990 0.5 1991 0.5 1992 0.5 1993 3.842 1994 7.183 1995 1.5 1996 1.8 1997 0.699 1998 0.711 1999 0.791 2000 0.777 2001 1.097 2002 1.305 2003 1.221 2004 1.42 2005 1.349 2006 1.37 2007 1.701 2008 1.671 2009 1.639 2010 2.072 2011 2.078 2012 1.986 2013 1.902 2014 1.722 2015 1.322 2016 1.322 2017 1.322 2018 1.322 2019 1.322 2020 1.322 2021 1.322 2022 1.322 2023 1.322 2024 1.322