Year % of total labor force 1991 29.424931129476583 1992 30.022041879571187 1993 30.298209444651874 1994 30.203294444971384 1995 30.86453164937603 1996 31.53734610901026 1997 32.23742336215898 1998 33.17370036077908 1999 32.92574612792155 2000 33.252700989684485 2001 33.561743044645745 2002 33.870657402458576 2003 34.19607762646114 2004 34.53079251160819 2005 34.85966524263752 2006 35.19132049368333 2007 35.5279959418566 2008 35.8661847524586 2009 36.20792735146315 2010 36.49080021436394 2011 36.71508413281927 2012 36.94352302899041 2013 37.16807410180679 2014 37.33624598682686 2015 37.76471263414976 2016 38.195349981547544 2017 37.99565811883801 2018 38.290145728878684 2019 38.50183101900936 2020 38.534932221063606 2021 39.12786242336819 2022 39.411459571616916 2023 39.51037545247916