Year	% of total
1960	0
1961	0
1962	0
1963	0
1964	0
1965	0
1966	0
1967	0
1968	0
1969	0
1970	0
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
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0
1997	0
1998	0.06344290657439446
1999	0.5949410029498525
2000	1.1417399267399269
2001	1.1852929292929293
2002	0.8904415011037529
2003	2.45011135857461
2004	3.5595421245421246
2005	3.38909426987061
2006	3.359968404423381
2007	3.3222393162393162
2008	2.2238580645161288
2009	1.5777183833116035
2010	2.3940605095541403
2011	1.9274638633377135
2012	1.2481572769953053
2013	1.3452309782608696
2014	1.4103846153846153
2015	1.4467678300455236
2016	1.628529862174579