Year	% of total
1960	95.08996645318695
1961	94.48105436573312
1962	91.19318181818183
1963	92.6599171652094
1964	88.34266749637005
1965	85.22727272727273
1966	94.53502956459417
1967	92.17961654894047
1968	83.06115914185078
1969	92.05075845974329
1970	78.03172895939768
1971	78.14083080040527
1972	80.15837104072399
1973	74.80596405228758
1974	73.26158165652784
1975	59.90094383702458
1976	47.65080629106112
1977	72.34845735027223
1978	74.0530173299541
1979	69.58113558796153
1980	52.70945679337103
1981	36.30642361111111
1982	45.06739597577652
1983	44.457984822467175
1984	50.87262307892681
1985	56.84742158426369
1986	41.88517735032223
1987	45.53051783315923
1988	54.5628902765388
1989	22.775842498727936
1990	32.263072471949755
1991	30.38213132400431
1992	15.558856294095804
1993	27.49596644078735
1994	34.00140422544201
1995	25.14180545498431
1996	42.865444402475525
1997	38.377475682643855
1998	33.353895185956254
1999	16.91289555855898
2000	26.106704786498202
2001	30.397678045399413
2002	17.086527929901425
2003	33.79763977558522
2004	22.015749436723404
2005	10.242920239023123
2006	22.649044795783926
2007	21.51995905834186
2008	14.951072017592084
2009	16.74144133220161
2010	30.07580413849621
2011	22.240209682392848
2012	12.335439705107952
2013	27.169826255590294
2014	29.964010084874616
2015	16.887346190596908