Year	% of total labor force (national estimate)
1991	0.11
1992	0.17
1993	0.52
1994	0.65
1995	0.8
1996	0.9
1997	1.03
1998	1.13
1999	16.25
2000	11.78
2001	10.91
2002	10.04
2003	9.17
2004	7.99
2005	7.26
2006	6.62
2007	6.33
2008	5.86
2009	5.74
2010	5.63
2011	5.42
2012	5.19
2013	4.97
2014	4.91
2015	4.96
2016	5
2017	5
2018	4.9
2019	5
2020	7.24
2021	6.04
2022	5.65