Year	% of total
1971	62.93279022403259
1972	59.77653631284916
1973	50.85910652920962
1974	48.595041322314046
1975	68.08846761453397
1976	75.07507507507508
1977	75.69141193595343
1978	74.82014388489209
1979	68.359375
1980	86.36363636363636
1981	87.74271844660194
1982	87.59036144578313
1983	87.04358068315665
1984	84.81561822125813
1985	87.192118226601
1986	90.22687609075044
1987	90.4874213836478
1988	90.85631349782292
1989	94.03578528827038
1990	95.14742014742015
1991	94.7310647639956
1992	90.85903083700441
1993	88.84816753926702
1994	84.16619876473891
1995	79.98960498960498
1996	86.27838104639685
1997	75.50807712350182
1998	96.65116279069767
1999	93.71478110099697
2000	86.36731391585761
2001	94.7935368043088
2002	96.24911535739561
2003	95.86310643098909
2004	60.24565608148592
2005	50.01406469760901
2006	41.64733178654292
2007	60.32504780114722
2008	60.355434039644564
2009	55.68445475638051
2010	51.213500189609405
2011	39.132142155900254
2012	31.615673644659154
2013	28.900858441339842
2014	41.64656697218202
2015	33.48689436060365