Year % of total labor force 1991 22.319631939679432 1992 22.738672668428215 1993 23.001091342906225 1994 23.207187481964564 1995 23.400792496504597 1996 23.59221541382584 1997 23.59795003332119 1998 23.699919007253314 1999 23.6908747531977 2000 23.691757241826984 2001 23.61476865978448 2002 23.537931095479284 2003 23.48255084540924 2004 23.573348848125086 2005 23.928326185282707 2006 24.30150398605874 2007 24.683701592813716 2008 25.108040120999842 2009 25.53265362733305 2010 25.95845702334368 2011 26.385378663705737 2012 26.815302041141038 2013 27.248685440123122 2014 27.68461962048685 2015 28.266807149789543 2016 29.00981155470643 2017 29.776555011297933 2018 30.567545720109244 2019 31.38592967329706 2020 31.40969779661927 2021 31.9195274788527 2022 31.64111041063749 2023 31.78467254856689