Year	% of total
1971	92.57803479899067
1972	92.97977040269959
1973	93.94615340573476
1974	94.30473231638963
1975	94.61513514115272
1976	94.89812376605877
1977	95.00169161098826
1978	94.96643402975621
1979	95.51552328545915
1980	95.59045911681694
1981	95.87247333284358
1982	96.29024352947992
1983	96.37264873440495
1984	96.63502635677737
1985	96.8054593865814
1986	96.70949372802225
1987	96.64208462603371
1988	96.80960868264802
1989	97.03790685160916
1990	97.07518941823041
1991	96.78392613030077
1992	96.89043597958738
1993	97.06969309893275
1994	97.28381842049417
1995	97.64906149756385
1996	97.55305252295733
1997	97.73134338493381
1998	97.66899137191383
1999	97.74743193408308
2000	97.74776520210135
2001	97.79525777046675
2002	97.85988423922095
2003	97.74188767741397
2004	97.715153379632
2005	97.41637437335207
2006	97.40923708267324
2007	97.45246967947763
2008	97.98065834018476
2009	97.99780649887309
2010	98.07114473271172
2011	97.96442993846934
2012	97.99512501393252
2013	97.99423711988126
2014	97.9470497334413