Year	Percent
1991	50.464
1992	51.268
1993	51.812
1994	52.748
1995	53.29
1996	53.858
1997	54.529
1998	54.197
1999	54.986
2000	55.339
2001	55.458
2002	56.215
2003	56.517
2004	58.844
2005	58.653
2006	59.343
2007	58.764
2008	58.664
2009	58.999
2010	60.199
2011	63.229
2012	64.149
2013	65.074
2014	65.81
2015	66.83
2016	66.93
2017	67.027
2018	67.129
2019	67.275
2020	67.558
2021	67.861
2022	68.299