Annual % of total
1960 8.79120879120879
1961 9.63855421686747
1962 19.801980198019802
1963 15.463917525773196
1964 21.50537634408602
1965 3.296703296703297
1966 41.04477611940299
1967 32.5
1968 33.333333333333336
1969 33.83458646616541
1970 2.3224653863331843
1971 3.463414634146342
1972 2.3255813953488373
1973 2.4981631153563555
1974 3.584229390681004
1975 4.246504401864319
1976 5.599513085818623
1977 6.9380733944954125
1978 5.687932359723289
1979 8.575653031049777
1980 9.802876931273307
1981 -40.149625935162085
1982 -27.320490367775836
1983 -1.084010840108401
1984 34.22562141491396
1985 47.175141242937855
1986 57.41626794258373
1987 35.91160220994475
1988 28.030788967286725
1989 24.84113229347198
1990 39.28928571428572
1991 48.4955325443787
1992 35.13782729805014
1993 41.50248062015503
1994 32.68413043478261
1995 24.202199999999998
1996 25.38093418259023
1997 25.143084479371314
1998 33.01150812064965
1999 36.93255369928401
2000 18.955823927765238
2001 20.92997679814385
2002 16.48467889908257
2003 15.995104761904763
2004 20.496443089430894
2005 21.986784232365146
2006 13.45921052631579
2007 27.02
2008 28.492894736842107
2009 23.64055181695828
2010 23.19938775510204
2011 27.934065620542086
2012 29.0068443197756
2013 23.61088319088319
2014 24.253758967001435
2015 27.53316053511706
2016 28.146084243369735