Year	Percent
1991	69.49378
1992	68.88534
1993	68.10888
1994	67.20731
1995	66.01226
1996	64.61314
1997	64.84392
1998	64.91536
1999	64.92049
2000	64.79191
2001	62.3762
2002	59.8808
2003	57.17407
2004	54.28853
2005	51.16087
2006	48.0757
2007	47.8425
2008	47.66101
2009	47.53298
2010	47.3064
2011	46.54665
2012	45.76432
2013	45.01055
2014	44.27059
2015	43.459
2016	42.66426
2017	40.5973
2018	39.3926
2019	38.30845