Year	% of total
1971	98.55771855644477
1972	98.50659368150183
1973	99.07335649815764
1974	98.65988188954309
1975	98.58966720901952
1976	98.55013709938967
1977	98.78726446189013
1978	99.02932961491004
1979	99.08979734259132
1980	99.2145883583525
1981	99.28962583565286
1982	99.28680016486493
1983	99.30286749432075
1984	99.38496836275921
1985	99.16787668498979
1986	98.8829667177154
1987	98.65157919315669
1988	98.9382568192821
1989	98.96742808251348
1990	98.90358253895984
1991	99.01763243653103
1992	99.10456079805482
1993	99.11163551898969
1994	99.02652613070657
1995	99.31263045003686
1996	99.40369197801667
1997	99.33086833661733
1998	99.42760424178134
1999	99.4894588657769
2000	99.78154823496075
2001	99.81939342400946
2002	99.63349547429097
2003	99.71246786969786
2004	99.72202118150295
2005	99.75418530603204
2006	99.8276264006328
2007	99.86390028528653
2008	99.86072752661578
2009	99.8622246851044
2010	99.929668893129
2011	99.92924194418016
2012	99.92804798158977
2013	99.92994945850883
2014	99.91950642326069