Year	Percent
1991	50.409
1992	50.123
1993	49.712
1994	49.239
1995	48.112
1996	47.192
1997	45.258
1998	44.317
1999	43.345
2000	47.322
2001	51.347
2002	55.446
2003	59.454
2004	63.29
2005	63.09
2006	62.864
2007	62.645
2008	62.447
2009	62.122
2010	61.862
2011	61.617
2012	61.623
2013	61.665
2014	61.667
2015	61.603
2016	61.441
2017	61.684
2018	61.901
2019	62.134
2020	62.358
2021	62.576
2022	62.792