Year	Percent of total labor force
1980	2.663
1981	4
1982	5.8
1983	7.9
1984	8.1
1985	7.8
1986	7.4
1987	7.4
1988	7.7
1989	7.5
1990	7
1991	7.7
1992	8.7
1993	9.7
1994	9.6
1995	10
1996	10.3
1997	10.3
1998	11.2
1999	12.125
2000	11.35
2001	10.775
2002	10.35
2003	9.775
2004	10.6
2005	10
2006	9
2007	8.4
2008	7.75
2009	9.6
2010	12.725
2011	17.85
2012	24.425
2013	27.475
2014	26.5
2015	24.9
2016	23.55
2017	21.45
2018	19.6
2019	18.463
2020	17.452
2021	16.229
2022	15
2023	14.305
2024	13.61