Year	% of total
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0.027487630566245192
1991	0.02685284640171858
1992	0.022614201718679332
1993	0.021003990758244065
1994	0.019700551615445233
1995	0.017806267806267807
1996	0.016507098052162432
1997	0.047892720306513405
1998	0.04447739065974796
1999	0.042366897330885465
2000	0.04067796610169491
2001	0.10597430123195126
2002	0.0983767830791933
2003	0.11258443832874655
2004	0.10036801605888257
2005	0.08286720530350114
2006	0.08093525179856115
2007	0.09999230828397815
2008	0.0867177337765573
2009	0.07006726457399103
2010	0.08120728158624889
2011	0.07510070321567557
2012	0.05422993492407809
2013	0.05213462318252911
2014	0.04390779363336992
2015	0.6889660250341854