Year	% of total
1960	97.24137931034483
1961	96.73202614379083
1962	96.66666666666669
1963	96.95652173913044
1964	96.91119691119691
1965	95.77464788732394
1966	95.80152671755725
1967	95.59322033898304
1968	95.83333333333331
1969	95.72649572649573
1970	95.56135770234987
1971	96.10705596107056
1972	96.34703196347031
1973	94.78957915831663
1974	93.98496240601504
1975	95.43726235741444
1976	94.89291598023064
1977	95.99483204134368
1978	96.23955431754875
1979	97.43040685224838
1980	96.20253164556962
1981	96.06164383561644
1982	97.5736568457539
1983	97.43589743589743
1984	97.22772277227722
1985	97.42173112338858
1986	97.73095623987034
1987	97.89473684210527
1988	97.71615008156606
1989	95.53349875930522
1990	101.08
1991	98.16864583333333
1992	100.67879464285714
1993	98.84231818181817
1994	94.35640316205533
1995	98.80143396226414
1996	95.57606382978723
1997	97.86761589403973
1998	91.88335227272727
1999	97.47590395480226
2000	92.79358090185677
2001	94.3342748091603
2002	92.6685221674877
2003	87.58706401766004
2004	92.57137777777778
2005	94.3186511627907
2006	93.26050997782706
2007	92.97062098501071
2008	93.23717488789237
2009	96.56154897494305
2010	93.9109756097561
2011	95.09599580712788
2012	91.87046908315565
2013	91.38915367483295
2014	90.98165966386554
2015	94.56267552182163
2016	97.46858736059481