Year	Percent
1991	44.265
1992	46.272
1993	47.283
1994	48.269
1995	49.228
1996	49.796
1997	50.274
1998	50.802
1999	51.128
2000	51.64
2001	52.437
2002	52.915
2003	53.972
2004	54.232
2005	56.03
2006	56.335
2007	55.838
2008	56.664
2009	57.183
2010	57.785
2011	57.767
2012	57.903
2013	58.544
2014	58.15
2015	58.511
2016	59.097
2017	59.224
2018	59.48
2019	59.743
2020	59.92
2021	60.122
2022	60.304