Year	Percent
1991	54.714
1992	54.458
1993	54.96
1994	54.897
1995	55.345
1996	55.674
1997	55.694
1998	56.514
1999	56.694
2000	57.111
2001	57.832
2002	58.525
2003	58.894
2004	59.699
2005	60.449
2006	60.123
2007	60.074
2008	60.929
2009	61.645
2010	62.336
2011	62.406
2012	61.349
2013	61.294
2014	62.792
2015	61.769
2016	62.1
2017	62.137
2018	62.447
2019	62.557
2020	62.702
2021	62.759
2022	62.899