Year	Percent
1991	62.758
1992	63.499
1993	63.063
1994	63.134
1995	61.798
1996	61.587
1997	61.042
1998	61.357
1999	61.104
2000	60.994
2001	60.577
2002	60.074
2003	60.299
2004	59.618
2005	59.34
2006	59.124
2007	58.678
2008	58.429
2009	54.2
2010	55.207
2011	59.587
2012	71.591
2013	53.921
2014	56.973
2015	58.374
2016	62.196
2017	62.116
2018	62.015
2019	61.91
2020	61.803
2021	61.696
2022	61.588