Year	% of total
1960	90.68476249228871
1961	90.18441403926234
1962	91.45216124332201
1963	90.88066701406983
1964	90.68883610451306
1965	90.35555555555555
1966	90.7724425887265
1967	86.56367041198502
1968	85.36478811708169
1969	85.04954760878933
1970	25.86475942782835
1971	27.597548213484828
1972	22.13740458015267
1973	29.31034482758621
1974	46.06072252113759
1975	55.9125315391085
1976	81.8804319199368
1977	82.33317330772924
1978	78.69203329369797
1979	77.54504504504504
1980	75.77937649880097
1981	74.90690939180803
1982	73.66846199880311
1983	71.96279422930904
1984	66.56916005014625
1985	70.16632016632018
1986	61.07670319199619
1987	61.90341711380967
1988	60.21828535273648
1989	48.79581151832461
1990	60.1141010320478
1991	65.56940469688695
1992	56.91351113412739
1993	36.71536494845361
1994	40.82364859813084
1995	41.423070580474935
1996	43.19483465027802
1997	53.67121325361236
1998	48.36484510809004
1999	44.38230905468231
2000	41.210928244881735
2001	44.657135193133044
2002	41.51101538925769
2003	45.4185481124042
2004	41.22878522377457
2005	42.90517492394611
2006	44.67337301587302
2007	34.630844562535586
2008	37.13453239245027
2009	34.562560734892195
2010	31.786883029978586
2011	39.994464501409205
2012	35.5196272153188
2013	36.66045238560177
2014	41.869412672045556
2015	39.798869502868065
2016	36.26541296288025