Year	% of total
1971	0.4393994145653225
1972	0.3861455514641013
1973	0.7754986528219141
1974	0.9876841961875269
1975	1.4048328036107374
1976	1.4412911182534465
1977	0.910619367556263
1978	1.1432600537666133
1979	1.0063904176484402
1980	0.8766289572226209
1981	0.8945352510016052
1982	0.5667777773858806
1983	0.9420054009908052
1984	1.5466274388899277
1985	1.8251398819675129
1986	2.0541124161042315
1987	1.7142413395733316
1988	1.971982998418438
1989	1.7508281925822138
1990	1.9664385601832084
1991	2.002059178736495
1992	1.947650811506358
1993	1.7216144093237444
1994	1.780567992857382
1995	2.0962025149078864
1996	2.05896202415766
1997	2.2071946821336637
1998	2.152574159458248
1999	2.097603266668707
2000	2.102210986058868
2001	2.1219190274539668
2002	2.0537037511366982
2003	1.9932666591532575
2004	1.8948230095797467
2005	1.745876234920975
2006	1.681550172310099
2007	1.580303699856595
2008	1.454049311058896
2009	1.5996961475087619
2010	1.5654599393708182
2011	1.8254714419483793
2012	1.7097321583287295
2013	1.8934917915913139
2014	1.7796983681481506
2015	0.26374168579996987