Year	% of total
1960	20.416666666666664
1961	12.6360338573156
1962	7.179818887451487
1963	4.662162162162162
1964	4.99675535366645
1965	4.002223457476376
1966	3.218790778599391
1967	2.2589052997393573
1968	2.2258195062727646
1969	4
1970	6.446120165409876
1971	4.832056570418385
1972	2.2894838960031043
1973	2.1439509954058193
1974	2.1951499827606025
1975	2.4728105323411564
1976	1.4978468451600824
1977	1.444327731092437
1978	0.9148486980999296
1979	1.961257133670927
1980	2.420066152149945
1981	4.114024005053696
1982	5.033149687179008
1983	5.985645599609783
1984	5.667870036101083
1985	4.231951231800092
1986	3.5767511177347244
1987	3.530950305143854
1988	3.546935744550736
1989	3.7335654404691008
1990	4.33731182795699
1991	4.020881386316104
1992	3.597162938331318
1993	2.620355247039608
1994	3.198054507337526
1995	2.6504804928131414
1996	1.971891891891892
1997	1.898199917616367
1998	2.833635631875503
1999	2.804399019860717
2000	2.505635577045426
2001	2.805301591547412
2002	3.2469891804501922
2003	3.3284673187022897
2004	2.2678466250441747
2005	2.657843577930105
2006	2.8827509333333334
2007	2.9986808595304417
2008	2.895092797384364
2009	1.414511838254855
2010	1.0760509103765246
2011	0.887728119180633
2012	0.8194575173720784
2013	0.5588992379339544
2014	0.3936193357827246
2015	0.3441659245050353
2016	0