Year	% of total
1971	0
1972	0
1973	0
1974	0.4794076170225305
1975	1.0946364093917793
1976	1.0224218672420542
1977	0.589997651281724
1978	0.955470216038364
1979	0.7966333687691951
1980	0.6340155363170125
1981	0.7342488321564542
1982	0.45954645401219574
1983	0.7905510737165399
1984	1.3569029437862492
1985	1.8590903234094722
1986	1.1111967117954342
1987	1.337589581768845
1988	1.1003969617505729
1989	1.2023811988873394
1990	2.0323394170598816
1991	2.071266360539548
1992	1.909021623800762
1993	1.8686518822804188
1994	1.6906617431263686
1995	2.312325663320033
1996	2.171590650275027
1997	2.491100177583208
1998	2.1904313923341
1999	2.2312473437339393
2000	2.0526721958097913
2001	3.0411158967401493
2002	2.886667130695658
2003	2.9222008915113387
2004	2.552697055106646
2005	2.346888874186947
2006	2.6513096851935996
2007	2.3544437423868065
2008	2.3502902396854113
2009	2.3806425910436952
2010	1.9774500391047525
2011	2.1901785288485267
2012	2.055451572177191
2013	2.155572728582247
2014	1.9491895860093966
2015	0.7276932261333181