Year	%
1971	63.4553
1999	98.01144
2000	98.21321
2001	98.34016
2002	98.5079
2003	99.11776
2004	98.86839
2005	99.01726
2006	98.46354
2007	98.86903
2008	98.51525
2009	99.3647
2010	98.7953
2011	99.35887
2012	98.94146
2013	99.23799
2014	98.61963
2015	99.22121
2016	99.17383
2017	98.92097