Year	Percent
1960	-26.72065
1961	-32.94118
1962	-33.44482
1963	-36.0119
1964	-34.23181
1965	-37.7551
1966	-45.67901
1967	-44.64918
1968	-43.0622
1969	-37.98812
1970	-36.65988
1971	-42.04753
1972	-53.05466
1973	-53.50773
1974	-63.41463
1975	-89.51175
1976	-120.71651
1977	-100.5354
1978	-73.33909
1979	-101.51453
1980	-89.08063
1981	-97.71654
2007	-54.09167
2008	-52.22134
2009	-64.71842
2010	-61.66525
2011	-50.27581
2012	-61.63782
2013	-53.25649
2014	-46.67534
2015	-41.37575
2016	-40.88789