Year % of total labor force (national estimate) 1991 12.428054924580065 2002 12.741631840217462 2004 11.2117174945408 2005 11.332937368473745 2006 10.576708061327167 2007 9.85022187621919 2008 9.53698606639912 2009 9.74999102215987 2010 10.15866745851762 2012 10.805984484838815 2013 10.504273010969358 2014 10.551634857223117 2015 10.545730820657141 2016 10.08816290864957 2017 10.603791868369632 2021 9.000523913876782