Year	% of total
1960	39.48863636363637
1961	64.3027888446215
1962	76.34245187436677
1963	-28.29131652661065
1964	42.608695652173914
1965	54.83415666901905
1966	32.09764918625678
1967	35.0197628458498
1968	21.59709618874773
1969	18.12206572769953
1970	37.286063569682156
1971	33.303167420814475
1972	35.89857651245551
1973	37.065938353492
1974	32.61583363735863
1975	28.391768292682922
1976	51.277918489523366
1977	47.585581500793474
1978	41.60287081339713
1979	42.46875685156763
1980	33.99004113444468
1981	38.474612279583596
1982	27.940298507462686
1983	12.055780476833108
1984	16.520284399832704
1985	16.431095406360424
1986	16.030373338958025
1987	15.571368773545416
1988	18.373006702103073
1989	13.789186733303044
1990	25.209000708717223
1991	24.59710769230769
1992	40.727367979882644
1993	33.05299117882919
1994	25.150775729646696
1995	24.827484802431613
1996	32.45157142857143
1997	16.59071169208424
1998	18.022914893617024
1999	27.56056298381422
2000	26.838558495821722
2001	22.31570317563189
2002	22.272103620474407
2003	26.95197127937337
2004	20.87227927363807
2005	21.047498729028977
2006	18.681566156615663
2007	23.02882646125963
2008	24.492923368022705
2009	26.4808618127786
2010	24.300764809902738
2011	21.72685640362225
2012	20.258019891500904
2013	22.150422349318085
2014	20.77743613138686
2015	23.647492944496708
2016	31.29924300603401