Year	% of total
1971	92.66666666666666
1972	86.03015075376884
1973	68.67119301648884
1974	92.7710843373494
1975	95.9094865100087
1976	94.34276206322795
1977	96.34809634809635
1978	98.62815884476535
1979	95.80327868852459
1980	88.66906474820144
1981	83.97435897435898
1982	77.83155856727977
1983	57.5685903500473
1984	92.4812030075188
1985	97.19967532467533
1986	99.73604826546003
1987	80.42113040265977
1988	92.78313683458379
1989	98.0405878236529
1990	99.84126984126985
1991	92.2712466686408
1992	81.92090395480226
1993	95.40085448605177
1994	93.20720310006838
1995	92.71137026239067
1996	71.78807947019867
1997	66.99708454810495
1998	68.88967094844273
1999	67.43208279430789
2000	45.64534551684751
2001	45.848694882760654
2002	37.98504303654579
2003	42.716433385173666
2004	35.95628415300546
2005	37.012012012012015
2006	48.77894736842106
2007	39.86466013533986
2008	41.269365317341325
2009	38.86441017424394
2010	52.16183686695677
2011	39.620861211185456
2012	27.661541046970843
2013	57.53971554520503
2014	36.52997351737421
2015	45.28144439387043