Year Percent of total labor force 1990 15 1991 14 1992 12 1993 10 1994 9 1995 12.5 1996 13.8 1997 12.7 1998 14.3 1999 12.8 2000 11.4 2001 9.066 2002 10 2003 12.9 2004 11.6 2005 11 2006 9.372 2007 8.54 2008 8.2 2009 13.054 2010 13.513 2011 13.972 2012 14.431 2013 11.68 2014 11.056 2015 10.114 2016 7.974 2017 8.987 2018 8.717 2019 10.089 2020 10.55 2021 11.277 2022 12.082 2023 12.862 2024 13.656