Year	Percent
1961	6.25748
1962	0.02222
1963	5.16406
1964	-8.74322
1965	7.9317
1966	6.29619
1967	14.79196
1968	-5.76958
1969	11.82772
1970	0.51031
1971	2.96325
1972	4.40202
1973	61.40578
1974	44.54272
1975	80.56976
1976	-17.63042
1977	-3.21016
1978	25.61889
1979	12.56451
1980	17.55507
1981	9.89469
1982	9.85581
1983	8.48776
1984	7.87557
1985	18.49512
1986	8.2544
1987	11.11963
1988	7.49584
1989	8.33797
1990	6.53274
1991	2.72953
1992	2.58216
1993	0.15552
1994	3.96622
1995	7.14494
1996	19.14321
1997	3.80023
1998	4.73621
1999	3.78104
2000	3.44666
2001	3.26116
2002	3.89287
2003	5.81582
2004	4.56214
2005	4.58636
2006	5.87597
2007	6.47122
2008	7.86097
2009	6.76435
2010	7.14465
2011	7.85945
2012	8.1646
2013	7.17496
2014	5.66875
2015	5.87278
2016	6.72786
2017	6.27868