Year	Percent
1991	72.686
1992	71.865
1993	71.107
1994	70.229
1995	69.339
1996	68.338
1997	67.368
1998	66.594
1999	65.843
2000	65.363
2001	64.744
2002	65.66
2003	66.504
2004	67.405
2005	66.429
2006	65.924
2007	65.548
2008	63.925
2009	63.028
2010	61.615
2011	62.552
2012	62.386
2013	63.672
2014	63.349
2015	63.817
2016	64.018
2017	63.761
2018	63.595
2019	63.342
2020	62.998
2021	62.589
2022	62.112