Annual % of total
1960 26.100366253293068
1961 22.244191794364802
1962 14.876313114198576
1963 23.35094930514778
1964 19.830266908525527
1965 22.326114495988417
1966 18.621399176954732
1967 19.829507466012924
1968 20.56539471478854
1969 23.288690476190478
1970 23.036443220380658
1971 17.044721880311823
1972 22.314679167887487
1973 20.12682657843948
1974 41.456391234320854
1975 50.41659483997012
1976 45.93298375751375
1977 47.134637514384345
1978 52.1567371343156
1979 50.71117283654998
1980 54.878442775220094
1981 58.07416267942585
1982 57.19613693467337
1983 56.19756587498523
1984 52.236340033830295
1985 57.43147833013504
1986 54.04934882319462
1987 52.66809846357179
1988 52.87428932406822
1989 55.836280949974736
1990 66.33813518231186
1991 59.06810333040335
1992 70.48341575178996
1993 62.92231069547848
1994 57.5492658388471
1995 51.32043954164529
1996 35.7632856158616
1997 40.86494224968734
1998 58.486048898279506
1999 71.07329463445247
2000 63.14585460227696
2001 73.39341976837352
2002 86.31480217062784
2003 92.53266908037654
2004 61.39155037130447
2005 60.70319730913245
2006 65.52111148175328
2007 56.133086136928924
2008 62.60748119151018
2009 64.1104251814799
2010 66.48951341890314
2011 59.30593548007992
2012 62.74352036100691
2013 55.28830935635124
2014 55.338894611096364
2015 51.16464630779848
2016 47.497221399481674