Year	% of total
1971	0.3024701730801546
1972	0.1590330788804071
1973	0.46546546546546547
1974	0.38482682792743267
1975	0.5076820307281229
1976	3.221323900960081
1977	3.084057971014493
1978	3.0009128251939754
1979	2.709412780656304
1980	1.8941282025720267
1981	2.7250744047619047
1982	2.406558533145275
1983	0.7114772514510391
1984	2.1168069370058658
1985	2.221121294690777
1986	2.371022551745443
1987	2.1419391689276024
1988	2.3170011806375443
1989	1.7848036715961242
1990	1.701911935110081
1991	1.5398425631818808
1992	1.3641213229690596
1993	1.1885467314964884
1994	0.3718643640489096
1995	1.1273538156590686
1996	1.540064844835572
1997	1.8164595754165043
1998	3.962314939434724
1999	4.464285714285714
2000	3.957015165210405
2001	4.206372124362306
2002	4.981121775917755
2003	5.745070668295236
2004	9.618635332921047
2005	17.83991529079572
2006	17.643833613568244
2007	27.476529350840266
2008	31.177921677459143
2009	31.671171307965622
2010	34.06519921983839
2011	35.66274889733065
2012	39.16034927068478
2013	41.516112720084585
2014	45.69172899444517
2015	45.02704607158401