Year	% of total
1971	3.0858449034879785
1972	2.4302536947759426
1973	2.3667529349986873
1974	2.4257602862254024
1975	2.2151790887094025
1976	2.075059571088165
1977	1.650572301237158
1978	2.261171262786385
1979	1.806540740150368
1980	2.062660555079837
1981	2.3018100363037153
1982	1.8377375520232664
1983	2.0928772411227126
1984	1.2920873548903615
1985	1.3409919363746823
1986	2.0672203742628
1987	1.9523818674455697
1988	3.0356390919879033
1989	1.7124982677040645
1990	1.30074891604257
1991	1.7268709322492213
1992	1.492457185805551
1993	1.916331038066779
1994	3.639915047979289
1995	2.8471237782585987
1996	2.7509112303762593
1997	2.6224791833799
1998	2.4428471058747228
1999	2.617221966768986
2000	2.0031492520526375
2001	1.511402097320091
2002	0.9602974435484826
2003	1.0181462566554385
2004	1.6752358608296312
2005	2.066527002303514
2006	1.865835742825328
2007	2.179397663268631
2008	1.5928752343672907
2009	1.4394803106980865
2010	2.405339166393907
2011	2.8358612172436417
2012	2.920509927964196
2013	2.548929377759243
2014	2.217283664634941
2015	2.0295673889498262