Year Percent of total labor force (Units) 1996 31.992 1997 36.104 1998 34.481 1999 32.411 2000 31.727 2001 30.515 2002 31.944 2003 36.687 2004 37.150 2005 37.250 2006 36.025 2007 34.925 2008 33.775 2009 32.175 2010 32.050 2011 31.375 2012 31.000 2013 29.000 2014 28.025 2015 26.050 2016 23.750 2017 22.375 2018 20.725 2019 17.250 2020 16.375 2021 15.425 2022 14.375 2023 14.300 2024 14.100 2025 14.000 2026 13.900 2027 13.900 2028 13.900 2029 13.900