Year	Percent
1971	60.75227
1972	56.16122
1973	53.97105
1974	51.27855
1975	60.16175
1976	82.61427
1977	68.60668
1978	74.36975
1979	75.35044
1980	81.49876
1981	93.00402
1982	90.99865
1983	93.64444
1984	94.6004
1985	96.06152
1986	96.84202
1987	97.02762
1992	55.78192
1994	78.36172
1995	71.69616
1996	101.06777
1997	99.65685
1999	100.27109
2000	99.18657
2001	87.03389
2002	93.11078
2003	98.14266
2004	100.28146
2005	111.30587
2007	106.19069
2010	97.41728
2011	98.7135
2012	97.75116
2013	99.62895
2016	100.65792