Year	% of total
1971	99.81977170102098
1972	99.94561604394715
1973	99.66977727746152
1974	99.88121039734914
1975	99.87513912429837
1976	99.88492050455787
1977	99.99032058741261
1978	99.99110972495829
1979	99.97178873154488
1980	99.96480681341623
1981	99.96427509169862
1982	99.96790967327529
1983	99.98791252808982
1984	99.9533024619539
1985	99.9580459552558
1986	99.96126381750182
1987	99.96438979816429
1988	99.97083433914547
1989	99.97502649377108
1990	99.93540594901988
1991	99.78131982365892
1992	99.90828691009852
1993	99.97008027916402
1994	99.98470424086878
1995	99.95523924592628
1996	99.9747167666058
1997	99.9999863896664
2000	100
2001	99.99999499393792
2003	100
2006	99.99999999999999
2007	99.99999999999999
2008	100
2009	99.99609680919245
2011	95.78056162044145
2012	92.57270196909376
2013	96.49017475874007
2014	93.68988945127069