Year	% of total
1960	99.3003434677522
1961	99.34301623309666
1962	99.66952553308678
1963	99.4745928094273
1964	99.60654705697198
1965	99.80221997981836
1966	99.65245124095351
1967	99.8108685067975
1968	99.83748735552128
1969	99.59551420040275
1970	99.36572872440999
1971	99.5545271376401
1972	99.7410936205468
1973	99.7781703159019
1974	99.92694349862367
1975	99.9082699189933
1976	99.88296821855685
1977	99.6830493695589
1978	99.83547545120548
1979	99.83566701184098
1980	99.83641791044776
1981	99.86338356945386
1982	99.71110416419631
1983	99.697195521135
1984	99.6921773510308
1985	99.66319150385968
1986	99.51896219973932
1987	99.48941745421615
1988	99.56554348223759
1989	99.58031606657751
1990	99.61681097926997
1991	99.6119859265758
1992	99.62343739326457
1993	99.59488130439867
1994	99.39460306437684
1995	99.41754879664927
1996	99.20151292288296
1997	99.34928593407787
1998	99.37473696867673
1999	99.3171800763777
2000	99.5137217477949
2001	99.28787491654785
2002	99.33353808353809
2003	98.88533688325568
2004	98.79571689356716
2005	98.86553244198332
2006	98.47139958093415
2007	98.19560362054779
2008	98.47518006756518
2009	95.6512112628742
2010	94.73539005826125
2011	95.18873150273008
2012	96.65584681268923
2013	96.04154800803381
2014	95.90302069024116
2015	95.82551659926905