Year	% of total
1960	98.31103862238947
1961	98.19956636876674
1962	98.12457970401019
1963	97.68107568590624
1964	98.19371148817707
1965	98.27097545829727
1966	96.82702205897952
1967	97.11396216919171
1968	97.90572894114278
1969	97.28685525930243
1970	91.15887768629977
1971	92.20331017636022
1972	93.2623520389979
1973	94.53948002861384
1974	94.18104388101524
1975	94.6878129986745
1976	95.2060267756014
1977	95.47634486343203
1978	95.01070221698214
1979	94.94150677877221
1980	94.68905639416842
1981	94.74596442976254
1982	94.56292028812162
1983	94.8361202552001
1984	94.39760852388007
1985	95.70018890031871
1986	94.97225998619818
1987	95.58043796109243
1988	96.17815002680695
1989	96.63051869327862
1990	94.5633807165641
1991	94.05584414124482
1992	94.32196258207462
1993	94.16119400965019
1994	94.27011350365554
1995	93.85006003955132
1996	93.46299998953175
1997	93.5109472268787
1998	94.08694814506546
1999	94.1798350397627
2000	94.59119325030727
2001	94.387342657927
2002	94.07165971727615
2003	93.98922591951074
2004	93.77944440137203
2005	93.41073803058507
2006	92.8859917071343
2007	93.02602135451424
2008	92.78015423089391
2009	92.37083310567317
2010	90.38560275532956
2011	90.85296403667564
2012	90.14823362840765
2013	88.00125275958955
2014	86.04931717838214
2015	82.57463513368832