Year	% of total
1971	7.333333333333333
1972	13.969849246231156
1973	31.328806983511154
1974	7.228915662650602
1975	4.090513489991297
1976	5.657237936772046
1977	3.651903651903652
1978	1.371841155234657
1979	4.19672131147541
1980	11.33093525179856
1981	16.025641025641026
1982	22.168441432720233
1983	42.4314096499527
1984	7.518796992481203
1985	2.800324675324675
1986	0.26395173453996984
1987	19.57886959734023
1988	7.216863165416221
1989	1.959412176347096
1990	0.15873015873015872
1991	7.728753331359195
1992	18.07909604519774
1993	4.599145513948228
1994	6.792796899931616
1995	7.288629737609329
1996	28.211920529801326
1997	33.00291545189504
1998	31.11032905155728
1999	32.519404915912034
2000	54.197601370645344
2001	53.98908715528683
2002	61.81741216311556
2003	57.1021254536029
2004	63.861566484517304
2005	62.773487773487766
2006	51
2007	59.93334006665994
2008	58.4607696151924
2009	60.70498698177449
2010	46.88454772706231
2011	59.152513295591014
2012	70.75875976808672
2013	40.12309739665641
2014	60.797688789021755
2015	51.524806554392356