Year	%
1977	67.94958
1978	75.0156
1979	84.75827
1980	84.53979
1998	94.38373
1999	95.01361
2000	95.54549
2001	95.7725
2003	96.62992
2004	96.92163
2005	96.03033
2006	96.47194
2007	95.41946
2008	95.80817
2009	95.25839
2010	92.98795
2011	88.85211
2012	98.31446
2013	93.74088
2014	94.74466
2015	94.83554
2016	93.76628
2017	95.10198