Year	Percent
1961	8.61241
1962	8.90159
1963	7.69746
1964	5.43348
1965	-1.39111
1966	8.73082
1967	-1.68818
1968	-1.3993
1969	1.59626
1970	23.20259
1971	20.74808
1972	16.58163
1973	22.24394
1974	35.49811
1975	36.56802
1976	31.37294
1977	41.56204
1978	56.14297
1979	76.86142
1980	125.36748
1981	124.62136
1982	127.24437
1983	149.92104
1984	384.77032
1985	264.5367
1986	50.15993
1987	20.17887
1988	19.16523
1989	18.70287
1990	15.93207
1991	20.12977
1992	12.05813
1993	11.09025
1994	12.53793
1995	9.06893
1996	10.285
1997	8.77719
1998	6.91674
1999	6.23258
2000	2.82516
2001	1.85044
2002	4.17763
2003	-0.04317
2004	0.48118
2005	1.13477
2006	1.99221
2007	1.16999
2008	2.42711
2009	3.88473
2010	1.77372
2011	2.40469
2012	3.96014
2013	2.24833
2014	1.03925
2015	2.24444
2016	0.84329
2017	0.15221