Year % of total labor force 1991 37.30662057702701 1992 36.92884277383245 1993 37.16550889536963 1994 37.80523957687587 1995 38.46465157946778 1996 38.952567984981584 1997 39.33432846212902 1998 39.902243231484086 1999 40.6258295735973 2000 41.362976347009905 2001 42.447705131075146 2002 43.45617784448396 2003 43.72762154034798 2004 44.18676950971415 2005 44.68425500661654 2006 45.29852133567772 2007 45.90077064452615 2008 46.408483828428935 2009 46.75719580662361 2010 46.66926105855001 2011 47.39263033241205 2012 47.726585845570426 2013 48.139940978809726 2014 48.45438102538287 2015 48.69447387285657 2016 48.8918234479412 2017 49.17221968873612 2018 49.15289935695986 2019 49.50303285463348 2020 49.66811190623664 2021 49.858071311470745 2022 49.70814526615743 2023 49.78126510460194