Year	% of total
1960	93.09282886053674
1961	92.05548549810845
1962	93.30262225372077
1963	94.12515964240103
1964	94.17309340188518
1965	93.44348282192499
1966	94.17784853309075
1967	93.64440868865647
1968	93.85299934080422
1969	93.23067051652228
1970	94.73216928085232
1971	94.08480659311445
1972	94.23103591734849
1973	93.38525924203674
1974	93.91064136440068
1975	92.9988726042841
1976	93.12108559498957
1977	92.33762346602813
1978	91.87866927592955
1979	91.95192307692307
1980	90.31714568880079
1981	90.3734264254734
1982	89.19740150880135
1983	87.61648374404638
1984	82.61949834358731
1985	81.54007059746372
1986	83.90458254865035
1987	84.34870414002019
1988	84.13840023325882
1989	86.87464867903317
1990	85.65910871694417
1991	90.06682606541129
1992	94.20324262520009
1993	87.05454909397388
1994	88.990613592233
1995	82.10401132686084
1996	74.1441428359757
1997	75.7058064516129
1998	74.64177765914854
1999	70.41369045975424
2000	69.69253996447603
2001	69.89659132133389
2002	64.54201535508638
2003	60.264940484151396
2004	60.97732835429769
2005	53.788927016645324
2006	54.62954808642847
2007	49.1818669527897
2008	51.16499674182198
2009	49.90563725490196
2010	49.81626301304296
2011	46.18588019415177
2012	47.08884397002044
2013	42.35797443762782
2014	42.1769974140408
2015	45.74797835840591
2016	44.980340217739354