Year	% of total
1971	92.57803479899066
1972	92.97977040269959
1973	93.94615340573475
1974	94.30473231638965
1975	94.61513514115272
1976	94.8981237660588
1977	95.00169161098825
1978	94.96643402975623
1979	95.51552328545917
1980	95.59045911681696
1981	95.87247333284361
1982	96.29024352947992
1983	96.37264873440496
1984	96.6350263567774
1985	96.80545938658143
1986	96.70949372802227
1987	96.64208462603372
1988	96.80960868264803
1989	97.03790685160914
1990	97.07518941823041
1991	96.78392613030076
1992	96.89043597958741
1993	97.06969309893273
1994	97.28381842049419
1995	97.64906149756385
1996	97.55305252295732
1997	97.73134338493381
1998	97.66899137191382
1999	97.7474319340831
2000	97.7477652021013
2001	97.79525777046675
2002	97.85988423922092
2003	97.74188767741397
2004	97.71515337963201
2005	97.41637437335208
2006	97.40923708267324
2007	97.45246967947763
2008	97.98065834018476
2009	97.99780649887306
2010	98.07114473271169
2011	97.96442993846931
2012	97.99512501393251
2013	97.99423711988125
2014	97.94704973344132