Year	% of total
1971	82.24651922487251
1972	83.05676981861622
1973	84.61926279973532
1974	85.51937006876932
1975	85.79917065547292
1976	86.85521858340822
1977	87.51701231223024
1978	88.77404857704865
1979	90.28759985963545
1980	91.37232329590303
1981	91.57370409120324
1982	92.24483062946689
1983	93.26320585685254
1984	93.38499004019627
1985	92.8790006808548
1986	93.41555508546186
1987	93.67183335937948
1988	94.28902491979835
1989	94.40860244890816
1990	93.85562463498792
1991	92.74238733762239
1992	94.14939376129986
1993	94.46996178065324
1994	94.15898926352286
1995	94.87096635469658
1996	94.86392329757632
1997	95.00692383036132
1998	94.8558582530761
1999	94.64784844799462
2000	94.99382528287015
2001	95.19902383603814
2002	94.78076731936235
2003	95.19202299103365
2004	95.19132121038216
2005	95.1701452703744
2006	95.44927661458068
2007	96.12584384209617
2008	96.46673110606093
2009	96.21598654093705
2010	95.89111880661649
2011	94.96438725352562
2012	95.01932948589047
2013	96.22709584866956
2014	95.47834279366126