Year	% of total
1971	86.22060090448042
1972	89.07287751107617
1973	91.39596663756859
1974	90.23800708209228
1975	90.54347076250725
1976	89.53742115904377
1977	90.15289062588798
1978	89.75044151719891
1979	91.31035934813119
1980	90.17412252962865
1981	90.34111952318202
1982	89.20329082178793
1983	88.25291558772143
1984	86.41829649002915
1985	85.37220563078083
1986	85.42424747407878
1987	85.76849736313682
1988	85.81809023969579
1989	86.54206484875276
1990	82.59663875504872
1991	82.6387967129349
1992	83.53538021147199
1993	83.98332315570951
1994	83.86518634632503
1995	84.90323688771608
1996	85.25520123245452
1997	84.87780924931204
1998	86.69319414722608
1999	86.64970852618133
2000	84.55707037383972
2001	86.919410960444
2002	88.97377256171954
2003	89.34119113443707
2004	89.03311743833213
2005	88.91524035290914
2006	90.11589564729192
2007	90.32654003495828
2008	85.97681496135118
2009	82.31687105848306
2010	82.65261778479541
2011	82.49309604119271
2012	80.82174271443803
2013	81.40787349480064
2014	80.97134480832271