Year	Percent
1991	50.689
1992	51.58
1993	53.122
1994	53.47
1995	53.751
1996	54.221
1997	55.212
1998	54.85
1999	55.232
2000	55.914
2001	55.771
2002	55.919
2003	55.606
2004	56.041
2005	56.005
2006	56.408
2007	56.412
2008	56.666
2009	56.752
2010	57.112
2011	57.711
2012	58.313
2013	59.08
2014	58.939
2015	59.287
2016	59.663
2017	59.424
2018	59.636
2019	59.817
2020	59.929
2021	60.068
2022	60.205