Year	% of total
1960	0
1961	0
1962	0
1963	0
1964	0
1965	0
1966	0
1967	0
1968	0
1969	0
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	8.974358974358974
1981	11.76470588235294
1982	16.176470588235293
1983	35.74144486692015
1984	40.22140221402214
1985	40.0735294117647
1986	36.58536585365854
1987	43.58974358974359
1988	41.48148148148148
1989	43.66197183098591
1990	37.28116666666667
1991	39.88666666666667
1992	36.67
1993	37.89233333333333
1994	39.198965517241376
1995	44.527857142857144
1996	41.25375
1997	36.10584615384615
1998	37.71771428571429
1999	35.59147058823529
2000	33.933432835820895
2001	35.55878787878788
2002	37.71771428571429
2003	36.18749999999999
2004	44.561012658227845
2005	33.775
2006	35.2032
2007	28.173292682926824
2008	31.55325581395349
2009	25.804814814814815
2010	24.089781021897807
2011	26.26716312056738
2012	20.372222222222224
2013	19.052011173184358
2014	20.1870202020202
2015	16.938934010152284
2016	18.24192893401015