Year	% of total
1971	0
1972	0
1973	0
1974	3.7066189624329158
1975	8.577855025048564
1976	8.512046597828965
1977	5.0504427235985565
1978	8.66184123945684
1979	7.151775988948221
1980	5.893315871656676
1981	7.25044414119828
1982	4.688361831218974
1983	7.918052228914261
1984	10.321131521594094
1985	12.738318789351597
1986	11.654388506826113
1987	12.423374776609851
1988	11.097500287103319
1989	9.976044821919979
1990	14.349625541978714
1991	14.463942711150066
1992	12.67156994327231
1993	12.586072495777575
1994	12.766056396980172
1995	10.543908080280534
1996	10.703728151996096
1997	11.011369609117818
1998	10.06998865048911
1999	8.830949333267053
2000	6.94747497469351
2001	7.8333240858902515
2002	6.892591145370798
2003	8.221232206889058
2004	7.856037538062198
2005	6.515247746253235
2006	7.1966613330339015
2007	6.7188009123493
2008	6.027762244663005
2009	6.693788498921414
2010	5.72475511523754
2011	4.917602562618193
2012	4.71513784128529
2013	4.46296322926703
2014	4.166726991067163