Year	%
1971	54.10267
1972	54.72698
1974	62.97829
1975	72.60478
1976	71.04683
1977	69.56912
1978	70.75166
1979	69.23226
1980	71.24979
1982	71.18536
1984	51.05949
1985	70.25876
1986	74.54516
1987	75.97028
1988	74.99884
1989	83.97633
1990	67.61008
1991	97.83254
1992	91.97176
1993	92.29408
1994	91.27161
1996	87.55424
1998	84.58477
1999	87.54521
2000	87.85028
2001	88.58268
2002	87.45422
2003	86.8894
2005	85.13095
2006	86.56635
2007	85.37586
2008	87.04564
2009	88.5696
2010	88.42962
2011	88.61595
2012	90.36503
2013	88.67527
2014	87.39631
2015	88.72606
2016	90.23321
2017	90.51535