Year	% of total labor force (national estimate)
1969	2.8
1970	2.4
1971	1.5
1972	1.3
1973	1.2
1974	1.3
1975	2
1976	2
1977	1.8
1978	2.1
1979	2
1980	1.9
1981	2.06
1982	3.35
1983	4.11
1984	3.8
1985	3.6
1986	3.12
1987	3.79
1988	3.55
1989	3.14
1990	3.25
1991	3.42
1992	3.59
1993	4.25
1994	3.535
1995	4.353
1996	5.291
1997	5.157
1998	5.493
1999	4.707
2000	4.694
2001	4.012
2002	4.86
2003	4.785
2004	5.969
2005	5.682
2006	5.32
2007	4.909
2008	4.198
2009	5.371
2010	4.883
2011	4.637
2012	4.909
2013	5.367
2014	5.674
2015	5.802
2016	6.064
2017	5.561
2018	4.933
2019	4.56
2020	5.201
2021	6.459
2022	4.992
2023	5.264