Year % of total labor force 1991 39.58368941958149 1992 39.50342459849091 1993 39.500289349240646 1994 39.5653910984099 1995 39.65403743264861 1996 39.65386279913521 1997 39.65771774980827 1998 39.7697307294414 1999 39.785574237818864 2000 39.83925114336662 2001 39.86186869105708 2002 39.884334384283804 2003 39.8979677053923 2004 39.91906766025306 2005 39.94729019204807 2006 39.902639131019406 2007 39.951401754240706 2008 40.030607984222264 2009 40.107942105849254 2010 40.181424168855834 2011 40.27779076857637 2012 40.362052578551946 2013 40.568667826887435 2014 40.74629143618364 2015 41.01152878552346 2016 41.14843804972759 2017 41.37170443542654 2018 41.41705589523713 2019 41.410193608361304 2020 41.37337680929064 2021 41.60044223398114 2022 41.29217883884525 2023 41.372478187933794