Year	% of total labor force (national estimate)
1975	10.55
1977	9.4
1980	9.1
1981	8.13
1982	11.46
1983	11.13
1984	13
1985	13.89
1986	12.94
1987	10.83
1991	10.12
1992	9.44
1993	7.8
1994	8.25
1995	8.72
1996	11.81
1997	12.14
1998	15
1999	20.06
2000	20.52
2001	15.04
2002	14.481
2003	13.221
2004	13.717
2005	11.062
2007	11.204
2008	11.273
2009	12.066
2010	11.153
2011	10.288
2012	9.959
2013	9.246
2014	8.799
2015	8.572
2016	8.922
2017	9.086
2018	9.36
2019	10.28
2020	15.983
2021	13.898
2022	10.547
2023	9.594