Year	% of total
1971	66.76557863501483
1972	67.87330316742081
1973	70.20280811232449
1974	10.575635876840696
1975	13.57615894039735
1976	12.838801711840228
1977	12.005649717514125
1978	8.21917808219178
1979	13.26530612244898
1980	17.316017316017316
1981	35.3448275862069
1982	21.12676056338028
1983	20.38369304556355
1984	18.341708542713565
1985	11.636363636363637
1986	21.29032258064516
1987	22.023809523809522
1988	21.958456973293767
1989	18.64406779661017
1990	23.568281938325992
1991	14.64968152866242
1992	9.85576923076923
1993	7.908163265306123
1994	7.088607594936709
1995	6.862745098039216
1996	5.46218487394958
1997	2.587064676616915
1998	0.3642191142191142
1999	0.2853437094682231
2000	0.4331683168316832
2001	0.353386621792175
2002	0.2674638137193203
2003	0.311726414229394
2004	0.33293494963291786
2005	0.10538200978547235
2006	0.08142769898893941
2007	0.018661358546902214
2008	0.006610696106299992
2009	0.005895183634970229
2010	0.006000240009600384
2011	0
2012	0
2013	0
2014	0
2015	0.7633204439311003