Year	% of total labor force (national estimate)
1969	1.89
1970	1.51
1971	2.55
1972	2.7
1973	2.46
1974	1.98
1975	1.62
1976	1.61
1982	3.14
1983	3.48
1984	3.07
1985	2.83
1986	2.23
1987	2.15
1989	1.46
1990	1.832
1991	3.243
1992	5.722
1993	9.33
1994	9.58
1995	8.897
1996	9.547
1997	10.359
1998	8.941
1999	7.607
2000	5.466
2001	4.73
2002	4.965
2003	5.555
2004	6.693
2005	7.486
2006	7.066
2007	6.161
2008	6.235
2009	8.351
2010	8.61
2011	7.804
2012	7.976
2013	8.052
2014	7.954
2015	7.432
2016	6.99
2017	6.718
2018	6.365
2019	6.833
2020	8.291
2021	8.803
2022	7.417
2023	7.611