Year	% of total
1971	99.63265146168459
1972	99.79287351075101
1973	99.88804109475188
1974	99.94753630382898
1975	99.86812218109479
1976	99.83150164661232
1977	99.7443438952654
1978	99.93122109511364
1979	99.991966705934
1982	99.97874023129798
1983	99.98909520059746
1986	99.02495302004651
1987	99.08380710867523
1988	99.17368073550544
1989	99.17411864623405
1990	99.39173802718754
1991	98.4536974522154
1992	98.6372976128307
1993	98.91353109242004
1994	99.08538294108598
1995	98.9279650752623
1996	98.97307486420218
1997	99.08530818175701
1998	98.98800801723029
1999	98.88756526760986
2000	98.91780932574366
2001	98.16821255940185
2002	98.15511934646347
2003	98.40424849887415
2004	98.71373917270255
2005	98.17112737288785
2006	98.30136457760584
2007	98.12869973951413
2008	98.24675266727078
2009	97.93284224831734
2010	97.68803285859974
2011	97.70145037457655
2012	96.32908939764675
2013	94.0061562567706
2014	90.57887358050316