Year	% of total
1971	92.43368227242964
1972	92.55055175722593
1973	92.52850396209445
1974	92.66968514233878
1975	92.76596348784508
1976	93.04387351818791
1977	93.26368130680898
1978	93.59976999973047
1979	93.89635852795394
1980	94.16360348605805
1981	94.23608622013825
1982	94.40522483753351
1983	94.52884350888277
1984	94.58479377342003
1985	94.50670457720405
1986	94.25604106571163
1987	93.85855102897584
1988	93.59510049139787
1989	93.54233887037583
1990	93.08860021840923
1991	92.88730556489725
1992	92.07253149182822
1993	91.64576078852379
1994	90.63293697101162
1995	89.86262835423075
1996	89.17157856613835
1997	89.67865695713797
1998	89.13749094241481
1999	89.76591755467595
2000	90.45489208849101
2001	90.56717780794278
2002	90.12492775566523
2003	89.83704463644185
2004	89.70140566037321
2005	89.81569661170802
2006	90.08915271992107
2007	87.98892581546224
2008	88.73478548671568
2009	67.72732473437276
2010	66.51085378733306
2011	63.55991562715673
2012	64.84206244938663
2013	59.93944795204508
2014	62.05199476356671