Annual % of total
1960 48.37988826815642
1961 50.52334943639292
1962 48.943794794417194
1963 49.284112471968264
1964 50.523648648648646
1965 48.982534850184265
1966 52.36386331721017
1967 49.910979228486646
1968 53.74224672639559
1969 51.88913583474963
1970 61.17996385231087
1971 59.758162031438935
1972 59.09143855562027
1973 58.11751904243743
1974 59.559710494571775
1975 57.19685361119624
1976 57.33127948397034
1977 57.221393961982855
1978 54.11278261634557
1979 53.189733432367746
1980 53.93518518518518
1981 51.8063345430551
1982 51.29781966296621
1983 51.0641453466815
1984 50.3481320655836
1985 51.69408019404229
1986 53.271097834204625
1987 53.42097617664149
1988 53.96448049223884
1989 55.28001653234139
1990 63.72594555873925
1991 63.31338671411625
1992 67.05489569629769
1993 64.65569200430261
1994 70.16232323232323
1995 53.874972908906194
1996 55.4006745964316
1997 54.76568485610945
1998 55.21383991262287
1999 54.4438249507786
2000 50.41337684644452
2001 48.780618169398906
2002 50.940303030303035
2003 52.96268654052124
2004 52.5590288153682
2005 53.469431877050596
2006 58.90579348579349
2007 57.90749957763136
2008 56.801829999999995
2009 56.80471886912325
2010 55.23744743351886
2011 50.59106708625375
2012 55.40931426945511
2013 58.50983931096542
2014 53.116830368328735
2015 54.25150684931507
2016 58.7350429799427