Annual % of total
1960 100
1961 100
1962 100
1963 100
1964 97.82608695652173
1965 93.07359307359307
1966 94.0959409594096
1967 93.72384937238493
1968 93.63957597173145
1969 92.97124600638978
1970 92.66862170087977
1971 93.04556354916068
1972 92.51559251559252
1973 93.36917562724015
1974 92.3076923076923
1975 91.90647482014388
1976 91.3884007029877
1977 92.28611500701263
1978 91.59347553324967
1979 90.55118110236221
1980 88.83928571428571
1981 89.73941368078177
1982 89.80667838312829
1983 90.94076655052264
1984 88.27838827838828
1985 89.48220064724919
1986 89.45147679324894
1987 89.49468085106383
1988 90.52369077306733
1989 89.76572133168928
1990 92.24996515679442
1991 97.66683006535948
1992 82.97139759036145
1993 84.3059090909091
1994 98.97119587628866
1995 92.17054054054054
1996 95.6819867549669
1997 100.61790645879731
1998 95.1082470119522
1999 98.65976190476191
2000 100.00909090909092
2001 93.09579335793359
2002 100.11175724637683
2003 97.99741379310345
2004 98.89787878787878
2005 91.58727272727273
2006 95.36435975609756
2007 87.86325000000001
2008 90.26086436170213
2009 91.67500000000001
2010 94.2795499296765
2011 85.33301480484523
2012 85.1531543624161
2013 85.9246915167095
2014 86.68731800766284
2015 85.40122015915121
2016 85.7297400990099