Year	Percent
1960	-2.51604
1961	-1.15143
1962	-2.47197
1963	-1.41822
1964	-1.62602
1965	-3.10656
1966	-7.00544
1967	-8.58224
1968	-3.70743
1969	-2.79422
1970	-2.45949
1971	-2.23989
1972	5.64719
1973	-9.59243
1974	-13.5324
1975	-8.89697
1976	1.15268
1977	-5.33516
1978	3.16041
1979	13.89222
1980	-19.03956
1981	-19.43683
1982	-10.0764
1983	-10.59231
1984	-13.00777
1985	-7.06006
1986	-8.05529
1987	-1.98968
1988	-40.28933
1989	-32.65466
1990	-21.3941
1991	-30.68401
1992	-36.01517
1993	-27.43011
1994	-12.80146
1995	-11.84962
1996	-14.78812
1997	-19.16644
1998	-18.34483
1999	-25.47709
2000	-21.08217
2001	-19.89631
2002	-20.39701
2003	-20.76507
2004	-21.07561
2005	-22.88146
2006	-24.77641
2007	-26.89858
2008	-27.85306
2009	-19.03062
2010	-19.42983
2011	-21.7935
2012	-20.23894
2013	-20.55567
2014	-16.68206
2015	-18.37115
2016	-16.89115
2017	-14.19718