Year	Percent
1991	52.702
1992	55.478
1993	53.305
1994	53.674
1995	53.606
1996	53.911
1997	55.597
1998	59.064
1999	62.512
2000	66.688
2001	68.982
2002	68.956
2003	68.149
2004	65.818
2005	64.855
2006	65.105
2007	67.918
2008	68.848
2009	68.465
2010	63.465
2011	62.572
2012	62.435
2013	60.91
2014	58.75
2015	61.639
2016	62.101
2017	63.044
2018	64.293
2019	64.704
2020	64.604
2021	64.524
2022	64.472