Year	% of total labor force (national estimate)
1971	9
1972	8.1
1973	7.1
1974	6.1
1975	5.2
1976	5.3
1977	5.3
1978	5.5
1979	5.6
1980	6.1
1981	10.16
1982	11.6
1983	14.19
1984	14.66
1985	19.28
1986	19.76
1987	20.32
1988	18
1989	10.1
1990	6.69
1991	6.59
1992	5.52
1993	5.99
1994	3.08
1995	3.69
1996	5.23
1997	2.08
1999	3.93
2000	4.47
2001	5.24
2002	5.48
2004	4.17
2005	5.45
2006	5.08
2007	5.18
2008	2.603
2009	2.973
2011	2.255
2012	2.066
2013	2.437
2014	2.021
2015	3.111
2016	3.498
2017	3.655
2018	3.519
2019	3.682
2020	7.903
2021	5.089
2022	3.552