Year	% of total labor force (national estimate)
1991	2.8366131610117535
1992	3.5959161213814816
1993	3.753125608501264
1994	4.055158319655385
1995	4.494937855450252
1996	4.539000622696205
1997	4.8239014710258585
1998	5.07828942018897
1999	5.3609062723510865
2000	5.165447046417139
2001	5.331447445214046
2002	5.622882959810641
2003	5.714947360978009
2004	5.5287601374177955
2005	5.551713956639663
2006	5.213696433852497
2007	4.90931921862263
2008	5.05341208463775
2009	5.342794462136998
2010	4.691638026769003
2011	4.851568575866359
2012	4.744647322973406
2013	4.676775206862403
2014	4.615287934722847
2017	4.89022313769869
2018	5.429592647798421
2019	5.569794822625845
2020	6.246487219665508
2021	5.8544629241367305