Year	Percent
1961	1.93395
1962	1.36074
1963	1.17683
1964	2.5475
1965	3.84628
1966	5.78874
1967	7.58155
1968	2.16615
1969	1.58436
1970	5.97859
1971	4.66418
1972	10.77542
1973	9.90661
1974	12.79692
1975	16.46728
1976	11.31553
1977	4.93738
1978	12.46681
1979	21.85636
1980	10.19028
1981	-0.08832
1982	3.69542
1983	8.74549
1984	15.42699
1985	22.89366
1986	14.06125
1987	12.69407
1988	22.69706
1989	13.64878
1990	6.30002
1991	5.17771
1992	6.63928
1993	13.0647
1994	9.4638
1995	7.15529
1996	16.1122
1997	5.28154
1998	9.66339
1999	14.23521
2000	14.17097
2001	8.31283
2002	1.18737
2003	3.25908
2004	10.07879
2005	15.47171
2006	7.47313
2007	4.92761
2008	4.72939
2009	6.46253
2010	8.92
2011	16.41481
2012	-0.1122
2013	0.45688
2014	11.9039
2015	1.86495
2016	11.95754
2017	3.1494