Year	Percent
1991	67.198
1992	66.753
1993	64.606
1994	66.229
1995	68.943
1996	68.821
1997	69.82
1998	68.973
1999	69.351
2000	68.807
2001	68.644
2002	69.076
2003	67.991
2004	68.263
2005	68.241
2006	69.141
2007	68.578
2008	68.952
2009	65.528
2010	63.298
2011	63.165
2012	62.294
2013	61.691
2014	62.033
2015	62.504
2016	63.505
2017	63.442
2018	63.537
2019	63.407
2020	63.316
2021	63.177
2022	63