Year	Percent
1991	40.66948
1992	40.45486
1993	40.78355
1994	41.27141
1995	41.22078
1996	41.52576
1997	41.56034
1998	40.83675
1999	39.77834
2000	39.05631
2001	38.13848
2002	37.17642
2003	36.13716
2004	34.93325
2005	33.66533
2006	32.35545
2007	30.8971
2008	29.45958
2009	28.08294
2010	26.81088
2011	27.09378
2012	26.60743
2013	27.18
2014	27.5421
2015	27.59403
2016	27.43327
2017	27.16344
2018	26.67335
2019	25.73098