Year	%
1971	75.46999
1974	83.04998
1975	91.3949
1976	89.37313
1977	91.07341
1978	91.42262
1980	90.35249
1981	89.8117
1982	90.03431
1983	75.12981
1984	79.5014
1993	60.70199
1998	67.81007
1999	68.70539
2000	70.25108
2001	73.06282
2002	73.29101
2003	74.0038
2004	78.58971
2005	77.9007
2006	79.10304
2008	97.16874
2009	96.99738
2010	95.31474
2011	96.82915
2012	99.13611
2013	99.95213
2014	95.7005
2015	98.63667
2016	99.00281
2017	99.59274