Year	Percent
1961	4.25758
1962	3.06226
1963	3.97455
1964	2.17246
1965	4.60349
1966	4.91569
1967	1.20866
1968	5.33953
1969	2.38867
1970	3.48743
1971	7.46481
1972	6.85845
1973	9.11447
1974	5.77718
1975	-1.61185
1976	8.82091
1977	5.04332
1978	3.95141
1979	6.61028
1980	4.81051
1981	4.40195
1982	3.47741
1983	3.75712
1984	5.11586
1985	-3.60966
1986	-1.57423
1987	2.13606
1988	6.69348
1989	5.89787
1990	5.97274
1991	6.64191
1992	6.11745
1993	7.17649
1994	6.52406
1995	7.10312
1996	7.24143
1997	4.62539
1998	-9.65575
1999	3.59466
2000	6.37365
2001	-1.65946
2002	3.2138
2003	3.68936
2004	4.72444
2005	3.34004
2006	3.62944
2007	4.37338
2008	2.95553
2009	-3.27707
2010	5.48782
2011	3.37139
2012	3.53784
2013	2.80378
2014	4.1786
2015	3.33536
2016	2.66891
2017	4.43837