Year	% of total labor force (national estimate)
1979	0.61
1980	0.57
1981	0.7
1982	0.56
1983	0.48
1984	0.34
2000	14.4
2001	15.73
2002	17.63
2003	16.36
2004	16.12
2005	16.47
2006	16.65
2012	13.59
2017	8.808