Year	% of total labor force (national estimate)
1970	7.1
1971	7.6
1972	6.79
1973	6.99
1974	5.8
1975	6.41
1976	6.67
1977	8.73
1978	8.06
1979	8.78
1982	8.41
1983	9.71
1984	10.08
1985	12.34
1986	10.53
1987	11.84
1988	16.33
1989	16.31
1990	11.6
1991	16.12
1992	14.67
1993	13.26
1994	14
1995	14.01
1996	14.32
1997	13.37
1998	14.02
1999	11.75
2000	13.53
2001	14.71
2002	14.11
2003	13.62
2004	12.44
2005	10.33
2006	9.11
2007	6.78
2008	4.868
2009	6.56
2010	5.832
2011	3.922
2012	3.714
2013	3.732
2014	4.444
2015	4.402
2016	4.843
2017	5.461
2018	5.313
2019	6.409
2020	18.548
2021	10.293
2022	8.281
2023	6.678