Year	Percent
1991	54.157
1992	55.853
1993	56.491
1994	58.219
1995	58.872
1996	58.743
1997	59.319
1998	59.718
1999	60.891
2000	61.608
2001	62.237
2002	62.988
2003	63.791
2004	65.031
2005	64.965
2006	65.264
2007	65.143
2008	65.91
2009	68.423
2010	68.809
2011	68.992
2012	69.441
2013	69.953
2014	69.704
2015	70.216
2016	70.514
2017	70.654
2018	70.835
2019	70.982
2020	71.087
2021	71.214
2022	71.338