Year Percent of total labor force (Units) 2003 1.800 2004 2.500 2005 3.100 2006 3.200 2007 3.700 2008 3.850 2009 4.000 2010 3.300 2011 3.100 2012 2.100 2013 2.900 2014 2.600 2015 2.500 2016 2.100 2017 3.138 2018 3.400 2019 2.720 2020 5.030 2021 4.800 2022 5.900 2023 3.500