Year	% of total labor force (national estimate)
1970	5.44
1971	5.44
1972	6.39
1973	6.37
1974	5.38
1975	5.82
1976	6.64
1977	7.12
1978	7.24
1979	7.64
1980	7.53
1982	9.03
1983	8.547
1984	9.432
1985	9.426
1986	10.565
1987	10.743
1988	10.998
1989	11.014
1990	9.806
1991	10.122
1992	9.342
1993	10.237
1994	11.109
1995	11.685
1996	11.893
1997	12.016
1998	12.14
1999	11.707
2000	10.856
2001	9.623
2002	9.231
2003	8.888
2004	7.881
2005	7.745
2006	6.79
2007	6.088
2008	6.737
2009	7.764
2010	8.381
2011	8.377
2012	10.678
2013	12.175
2014	12.717
2015	11.929
2016	11.725
2017	11.242
2018	10.639
2019	9.982
2020	9.19
2021	9.532
2022	8.092
2023	7.627