Year % of total labor force 1991 0.27421150481789613 1992 0.27211550759066205 1993 0.2702863413500262 1994 0.26844004123239035 1995 0.3109847821818159 1996 0.3087290946298779 1997 0.30385528432360676 1998 0.30171735431268876 1999 0.2616861949267539 2000 0.25842753734923984 2001 0.25700202003587747 2002 0.25484308037326014 2003 0.2527171303464415 2004 0.16628683981006717 2005 0.24680246835375347 2006 0.24433349893714928 2007 0.24185064110574112 2008 0.23938774191128767 2009 0.23042150036150935 2010 0.23323855441546132 2011 0.2283510312106639 2012 0.2251728977762784 2013 0.21784446367154905 2014 0.25907650116058767 2015 0.24478935698447896 2016 0.280433415167827 2017 0.2785203051746984 2018 0.412208864499672 2019 0.40343375920249214 2020 0.4127850538787691