Year	Percent
1961	8.54275
1962	1.59305
1963	4.71082
1964	3.90598
1965	-2.39468
1966	6.40435
1967	6.75979
1968	2.36764
1969	8.60746
1970	7.32064
1971	6.56187
1972	14.30545
1973	23.15158
1974	15.43909
1975	5.28427
1976	6.86602
1977	17.404
1978	24.90992
1979	23.97488
1980	22.02657
1981	24.97718
1982	30.59025
1983	26.05806
1984	33.63688
1985	46.16915
1986	28.64256
1987	25.89135
1988	78.8626
1989	36.73865
1990	66.23559
1991	88.77285
1992	109.23366
1993	97.48735
1994	159.26698
1995	104.55503
1996	32.56225
1997	47.58345
1998	17.66227
1999	15.82358
2000	9.85314
2001	1.6071
2002	7.38897
2003	9.67006
2004	15.67381
2005	8.62486
2006	9.37679
2007	6.66943
2008	14.24958
2009	3.95948
2010	19.58075
2011	21.00158
2012	34.8762
2013	34.9034
2014	33.89517
2015	17.90376
2016	-2.74534
2017	32.86136