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	1.3157894736842104
1985	11.479591836734695
1986	9.79498861047836
1987	5.95482546201232
1988	6.181818181818182
1989	11.544991511035652
1990	6.153846153846154
1991	6.301050175029172
1992	5.483870967741936
1993	5.156723963599596
1994	4.866412213740458
1995	4.545454545454546
1996	0.864100549882168
1997	2.0729092208720514
1998	6.046814044213264
1999	11.92429022082019
2000	20.41619797525309
2001	24.332810047095762
2002	25.94871794871795
2003	23.919308357348704
2004	21.709006928406467
2005	26.848591549295776
2006	33.95744680851064
2007	40.32454361054767
2008	44.153304653891276
2009	39.38688397361273
2010	38.67608776496839
2011	40.571219333577446
2012	41.11548087236325
2013	42.03601108033241
2014	42.90091930541369
2015	39.43943943943944