Year	Percent of total labor force
1990	6.3
1991	11.8
1992	13.6
1993	16.4
1994	11.4
1995	13.341
1996	12.343
1997	11.246
1998	10.576
1999	13.133
2000	16.087
2001	18.242
2002	19.934
2003	19.643
2004	18.974
2005	17.745
2006	13.843
2007	9.604
2008	7.119
2009	8.169
2010	9.635
2011	9.632
2012	10.088
2013	10.328
2014	8.988
2015	7.499
2016	6.161
2017	4.888
2018	3.79
2019	3.578
2020	3.486
2021	3.454
2022	3.47
2023	3.486
2024	3.502