Year % of total labor force 1991 1.8994955783964036 1992 1.8338059507294182 1993 1.762267585227666 1994 1.6959939008828857 1995 2.120772044344836 1996 2.069420589843851 1997 3.2819082681132006 1998 3.16382117403246 1999 3.4845003517253734 2000 3.4189864878338074 2001 3.3370563598422667 2002 3.3978402818401094 2003 3.2304281002665443 2004 3.262483075869044 2005 3.2170145580497667 2006 3.3142979508211767 2007 3.2602818699141674 2008 3.210678987471046 2009 3.1672246270194964 2010 2.9283085085641023 2011 2.865959127736485 2012 2.8086127011629003 2013 2.6895715509127753 2014 2.812222529076404 2015 2.7089677850609992 2016 2.6613627351828293 2017 2.626524316229551 2018 2.5929354696067883 2019 2.556034196028471 2020 2.7438014915170243