Annual % of total
1960 97.59036144578313
1961 97.97979797979798
1962 98.13084112149532
1963 98.21428571428571
1964 97.45762711864407
1965 97.33333333333333
1966 97.14285714285714
1967 98.49624060150376
1968 98.13664596273293
1969 96.47887323943661
1970 94.08866995073892
1971 95.37572254335261
1972 94.87179487179486
1973 95.78059071729959
1974 94.61538461538463
1975 91.70305676855895
1976 92.5531914893617
1977 91.45569620253164
1978 94.22110552763819
1979 94.21487603305785
1980 94.1031941031941
1981 94.45910290237468
1982 95.97855227882039
1983 94.55958549222797
1984 96.32352941176472
1985 98.58156028368793
1986 94.7136563876652
1987 93.02325581395348
1988 92.54237288135593
1989 92.81045751633987
1990 96.36946859903381
1991 97.4841089108911
1992 95.60923076923076
1993 95.96617021276596
1994 94.09038922155689
1995 96.5255291005291
1996 92.66075268817204
1997 93.86092457420925
1998 96.95651053864168
1999 96.95651053864168
2000 95.63369318181817
2001 96.6386187845304
2002 97.20460317460316
2003 96.70083756345177
2004 97.07851385390428
2005 96.13486486486485
2006 96.2228459530026
2007 97.10587341772151
2008 96.93863636363635
2009 97.50695652173913
2010 94.73083333333334
2011 95.67919540229884
2012 94.1527027027027
2013 93.47390566037737
2014 92.42403197158082
2015 89.40111459968603
2016 95.13685314685314