Year	Percent
1960	3.25268
1961	3.25296
1962	3.20201
1963	3.05395
1964	2.79325
1965	2.47456
1966	2.09457
1967	1.77248
1968	1.6469
1969	1.77714
1970	2.05755
1971	2.41537
1972	2.64905
1973	2.601
1974	2.19622
1975	1.57278
1976	0.87607
1977	0.30231
1978	-0.05204
1979	-0.0883
1980	0.10473
1981	0.40046
1982	0.62992
1983	0.71982
1984	0.59897
1985	0.35042
1986	0.02604
1987	-0.19094
1988	-0.13436
1989	0.30008
1990	0.9819
1991	1.81276
1992	2.49012
1993	2.76082
1994	2.51178
1995	1.95591
1996	1.23081
1997	0.70446
1998	0.68575
1999	1.36177
2000	2.4632
2001	3.77569
2002	4.73676
2003	4.94618
2004	4.27848
2005	3.14887
2006	1.75281
2007	0.71505
2008	0.59972
2009	1.73882
2010	3.61494
2011	5.6309
2012	6.9053
2013	7.06102
2014	6.01644
2015	4.33425
2016	2.61757
2017	1.25221