Year	% of total
1971	97.5216127997793
1972	97.35576063415078
1973	96.39014523202559
1974	95.28549316917353
1975	93.87004843753334
1976	91.36211265765817
1977	90.92420752786295
1978	91.41816151930637
1979	91.42822004366276
1980	91.36310761990346
1981	88.04475753721267
1982	87.4775167194143
1983	86.37279483273089
1984	86.13704994850964
1985	85.65053493965618
1986	86.75327583254335
1987	86.78503771849414
1988	84.21011574465591
1989	84.9239683151731
1990	84.12115556535645
1991	81.87300482864464
1992	82.48892414071834
1993	81.91968185766773
1994	79.84780035964292
1995	78.77100169420737
1996	77.48124011541731
1997	76.82164658973737
1998	76.14153182950476
1999	74.73726206330258
2000	72.3850411748848
2001	73.1454631425634
2002	70.46655610922483
2003	74.0906022391055
2004	73.97692939020605
2005	72.96125477667375
2006	72.47924390881741
2007	77.72065832627122
2008	76.14213637887583
2009	73.0238178824845
2010	73.16454291068418
2011	75.04395129785414
2012	72.18710038643913
2013	70.20847929050558
2014	71.04592252202693