Year	Percent
1971	11.44774
1972	5.69999
1973	7.66319
1974	15.55361
1975	16.42585
1976	13.19399
1977	6.98211
1978	9.27724
1979	7.50247
1980	11.55925
1981	14.92681
1982	13.01687
1983	9.71713
1984	8.87083
1985	7.42366
1986	4.12959
1987	4.62073
1988	6.35024
1989	5.34986
1990	5.09258
1991	3.22528
1992	1.54568
1993	1.04202
1994	0.46837
1995	2.05587
1996	0.9801
1997	0.4967
1998	0.97843
1999	1.06046
2000	2.11009
2001	3.40226
2002	3.10308
2003	6.53202
2004	-0.5376
2005	-3.22913
2006	2.23838
2007	-0.04752
2008	-2.01334
2009	5.53864
2010	2.0276
2011	2.88405
2012	3.44533
2013	0.89146
2014	0.87067
2015	6.13106
2016	-0.21756