Year	% of total labor force (national estimate)
1973	0.9
1974	2.1
1975	5.1
1976	5.3
1977	6.4
1978	7.3
1979	6.1
1980	7
1981	9.2
1982	10
1983	9.745
1984	8.868
1985	7.797
1986	6.033
1987	6.091
1988	6.486
1989	8.149
1990	8.338
1991	9.099
1992	9.027
1993	10.719
1994	8.036
1995	6.992
1996	6.844
1997	5.4
1998	5.039
1999	5.142
2000	4.476
2001	4.164
2002	4.274
2003	5.398
2004	5.204
2005	4.83
2006	3.897
2007	3.801
2008	3.683
2009	6.409
2010	7.747
2011	7.769
2012	7.798
2013	7.384
2014	6.925
2015	6.278
2016	5.989
2017	5.833
2018	5.131
2019	5.018
2020	5.637
2021	5.043
2022	4.434
2023	5.094