Year Percent of total labor force 1989 0.025 1990 2.9 1991 6.78 1992 13.24 1993 15.84 1994 14.05 1995 11.37 1996 10.988 1997 14.023 1998 12.367 1999 13.79 2000 18.134 2001 17.514 2002 17.416 2003 13.857 2004 12.192 2005 10.177 2006 9.022 2007 6.935 2008 5.664 2009 6.878 2010 10.306 2011 11.35 2012 12.379 2013 13.038 2014 11.524 2015 9.233 2016 7.666 2017 6.23 2018 5.2 2019 5 2020 5 2021 5 2022 5 2023 5 2024 5