Year	Percent
1991	73.385
1992	73.392
1993	73.121
1994	72.886
1995	72.63
1996	72.447
1997	72.402
1998	72.12
1999	71.955
2000	71.596
2001	71.542
2002	71.422
2003	54.517
2004	54.748
2005	54.677
2006	55.067
2007	54.393
2008	54.226
2009	53.858
2010	54.117
2011	46.386
2012	58.502
2013	49.827
2014	48.139
2015	48.349
2016	47.237
2017	47.344
2018	47.234
2019	47.145
2020	47.022
2021	46.888
2022	46.754