Year	Percent
1971	68.51207
1972	64.4482
1973	68.51051
1974	70.21439
1975	73.82899
1976	74.6721
1977	75.02036
1978	69.45777
1979	47.13214
1980	54.70032
1981	64.90989
1986	83.19417
1997	90.76707
1999	92.34136
2000	90.3494
2001	88.57091
2002	85.92899
2003	87.97145
2004	89.87942
2005	93.70523
2006	88.02666
2007	93.7442
2009	98.37309
2010	101.52978
2013	100.08266
2016	93.24413