Year	% of total
1971	92.88439654177584
1972	93.26555090595147
1973	93.37349898630507
1974	91.53779050470067
1975	91.64855828165372
1976	92.1308887183161
1977	92.37624729842526
1978	90.95194133134295
1979	91.36611180769953
1980	90.27525879139502
1981	90.01718166430939
1982	90.44518434756004
1983	89.16188633943682
1984	88.45826408715145
1985	87.15639950948228
1986	88.45046971593905
1987	88.16165855434517
1988	90.18100613041695
1989	91.3792509919561
1990	88.65260513438858
1991	88.85473895772543
1992	88.80594541650939
1993	87.68722885785905
1994	87.00193543986462
1995	87.09209566652393
1996	87.69628353424639
1997	86.89501343373762
1998	86.78511762728381
1999	88.27912241415503
2000	88.38751029232937
2001	85.99454411466752
2002	85.80340794875978
2003	86.01471381193222
2004	89.32496762554969
2005	89.05328414655119
2006	88.65322796276301
2007	89.22537849164975
2008	90.65178935419048
2009	89.61199314781845
2010	89.50324321283101
2011	88.85381112449156
2012	89.0249070672489
2013	88.96606441065762
2014	87.72240747968915