Year	Percent
1971	0.63319
1972	-1.22328
1973	8.68678
1974	3.36372
1975	5.36324
1976	5.02671
1977	4.92053
1978	4.15498
1979	6.20648
1980	12.39257
1981	7.78034
1982	3.44169
1983	-0.30548
1984	-0.17665
1985	0.63651
1986	3.51771
1987	3.05147
1988	1.85956
1989	2.14704
1990	3.15105
1991	3.35087
1992	3.55442
1993	2.85451
1994	3.56174
1995	0.78159
1996	2.10293
1997	5.58816
1998	1.37741
1999	3.14725
2000	7.33028
2001	2.70179
2002	1.29684
2003	-1.29698
2004	1.06396
2005	1.79639
2006	2.86405
2007	2.79756
2008	3.00032
2009	2.69005
2010	3.82986
2011	2.28809
2012	2.02765
2013	1.9069
2014	2.49072
2015	2.72389
2016	1.62842
2017	2.52883