Year	Percent
1975	0.65598
1976	-0.00967
1977	0.1504
1978	1.13196
1979	1.11908
1980	0.73355
1981	1.10983
1982	1.58336
1983	0.6632
1984	0.3975
1985	0.81512
1986	1.6701
1987	4.00127
1988	3.71694
1989	4.2947
1990	1.99675
1991	2.17445
1992	2.03658
1993	2.09807
1994	4.52933
1995	4.02603
1996	6.16945
1997	6.20512
1998	5.67291
1999	11.65435
2000	6.24192
2001	5.91683
2002	3.6565
2003	5.323
2004	6.85135
2005	6.06857
2006	4.90102
2007	7.76169
2008	10.28349
2009	8.03711
2010	7.3304
2011	9.5736
2012	11.34033
2013	7.48062
2014	9.10886
2015	8.62738
2016	4.94883
2017	2.31654