Year	% of total
1960	0
1961	0
1962	0
1963	7.975460122699387
1964	5.963302752293578
1965	7.761194029850746
1966	17.51412429378531
1967	11.313868613138686
1968	46.84385382059801
1969	46.68587896253602
1970	25.884016973125885
1971	32.20747889022919
1972	58.964143426294825
1973	55.71049136786188
1974	70.21709633649932
1975	69.40726577437857
1976	63.63636363636363
1977	60.824742268041234
1978	64.25873465533523
1979	66.36609558160504
1980	70.99023709902372
1981	66.27956989247312
1982	63.175549757733876
1983	79.76827094474153
1984	73.99442453205894
1985	80.89928057553956
1986	85.21478521478521
1987	78.69746551170998
1988	78.956888754899
1989	85.28584817244611
1990	97.41108938547485
1991	96.08602898550726
1992	81.05056234718828
1993	95.78529456771233
1994	91.71614061331339
1995	96.41447562776958
1996	95.02628087508822
1997	100.5754854368932
1998	98.5668794326241
1999	102.53359223300971
2000	101.74308564231738
2001	72.95965222696766
2002	73.127049941928
2003	72.29870267260578
2004	75.32382041271612
2005	69.10612077294687
2006	69.1514711111111
2007	90.75864841373316
2008	92.80752119499394
2009	97.83609381318237
2010	94.51205542725172
2011	93.37255474452554
2012	91.8889198343997
2013	91.10123435326844
2014	93.89558570483123
2015	92.35806862745098
2016	90.04792052980133