Year	Percent
1991	92.055
1992	91.916
1993	91.218
1994	90.465
1995	89.629
1996	89.843
1997	85.933
1998	85.572
1999	85.287
2000	84.738
2001	83.758
2002	88.032
2003	87.112
2004	86.641
2005	85.525
2006	84.262
2007	83.393
2008	82.66
2009	56.986
2010	56.474
2011	55.191
2012	54.308
2013	53.645
2014	53.367
2015	52.438
2016	51.577
2017	51.508
2018	51.403
2019	51.296
2020	51.188
2021	51.077
2022	50.963