Year	Percent
1971	1.80727
1972	4.9744
1973	10.4339
1974	8.92443
1975	7.20304
1976	1.51369
1977	3.06584
1978	6.33588
1979	4.28001
1980	11.53684
1981	1.81704
1982	16.5423
1983	23.30707
1984	59.40182
1985	32.31351
1986	112.89482
1987	94.26346
1988	79.54484
1989	99.25332
1990	30.24604
1991	67.89437
1992	64.98119
1993	49.05889
1994	23.24948
1995	44.73004
1996	39.23371
1997	34.13819
1998	8.07483
1999	12.30607
2000	80.89968
2001	6.76918
2002	1.79681
2003	-5.01183
2004	-1.38677
2005	5.80055
2006	-2.2727
2007	4.38103
2008	12.47521
2009	-2.45816
2010	2.96535
2011	14.03157
2012	-0.85053
2013	-0.93215
2014	-0.14826
2015	12.10199
2016	6.0964
2017	5.946