Year	% of total
1971	16.990291262135923
1972	16.990291262135923
1973	23.575498575498578
1974	15.687540348612009
1975	26.79778733866011
1976	27.925381571509327
1977	22.595656670113755
1978	22.80306444344299
1979	24.43796835970025
1980	24.77688057798555
1981	23.478587528174305
1982	17.2266139657444
1983	19.283425575298573
1984	22.617246596066565
1985	16.320671378091873
1986	9.375
1987	9.253624485412566
1988	10.319523008714263
1989	12.9304286718201
1990	11.433005690636316
1991	10.133010882708584
1992	8.949853834045424
1993	6.604388442320226
1994	8.65699100572363
1995	3.4425319267073844
1996	6.440648422520481
1997	6.063417102378142
1998	6.714795839155411
1999	5.764705882352941
2000	4.749223257878384
2001	5.709521619135235
2002	4.012858290918832
2003	3.7997159090909087
2004	3.0344771705222215
2005	2.8320792528453134
2006	2.5363177677694626
2007	2.4157393968714724
2008	2.7763165585364424
2009	1.1216612421658552
2010	1.7872027457710222
2011	1.9749507394741013
2012	1.6000164737860878
2013	1.6829819277108433
2014	1.052914316411496
2015	0.9591432105878565