Year	% of total
1971	91.05489707151683
1972	91.37081008372708
1973	95.81273279934038
1974	97.69178695801534
1975	98.24545053021433
1976	98.74276395247233
1977	98.90485151348042
1978	98.90083375237231
1979	99.0133011872545
1980	99.30294898220772
1981	99.33121717550644
1982	99.42918615903483
1983	99.50801908560672
1984	99.61514168126155
1985	99.67310818233898
1986	99.67353395342715
1987	99.72643549750069
1988	99.72447580735779
1989	99.8090373093357
1990	99.86999735941185
1991	99.9217502141883
1992	99.96137488271965
1995	100
2002	99.99990729521745
2003	100
2004	100
2005	100
2006	100
2007	100
2009	99.99993427119574
2011	99.99563632795706
2012	99.99553530166479
2013	99.99437899017737
2014	99.99518846988558