Year % of total labor force 1991 20.810532099871285 1992 20.964584850691914 1993 21.215805941943678 1994 21.442358841857285 1995 21.589636854087928 1996 21.811305820012752 1997 21.940940105609357 1998 22.02879633452763 1999 22.176365738818223 2000 22.42862439747868 2001 22.59067604910861 2002 22.83845673443897 2003 23.158546491482195 2004 23.503370900427488 2005 23.853318395398222 2006 24.429152158247657 2007 25.02108792040662 2008 25.62961071840777 2009 26.232653957564285 2010 26.800281691588836 2011 27.11444414785118 2012 27.376283294113 2013 27.598415688547558 2014 27.82945039979951 2015 28.092978028847266 2016 28.24802748618222 2017 28.490464036300473 2018 28.77622878578034 2019 29.0393152498223 2020 28.93221936371278 2021 29.390923947621207 2022 29.131845403593275 2023 29.289727817689503