Year	% of total
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	1.3555562332883935
1982	1.3320976651323182
1983	1.4097627088335147
1984	1.2500124182886412
1985	1.7685434693973638
1986	1.6359296026114578
1987	2.3144351119577133
1988	2.0668059625169284
1989	2.5014723177965803
1990	2.5321036418921206
1991	2.8561614527348076
1992	2.952540780510042
1993	3.2558773239164625
1994	2.775747640477466
1995	1.8904627229799564
1996	1.1961259034804728
1997	1.2345451934773841
1998	1.7474996582981466
1999	1.8115498080150547
2000	2.053434210393202
2001	2.101039251471428
2002	2.178497306245638
2003	1.888084674703255
2004	1.6618338721658372
2005	2.7721109319181902
2006	2.992089568616975
2007	2.5089839090690362
2008	2.8656326619507744
2009	2.230334144710611
2010	2.3746481827083348
2011	2.431361560639502
2012	2.2342104396949805
2013	2.4542900862779096
2014	3.3834302156469973
2015	3.7460526470173656