Year	Percent
1990	4.63847
1991	4.45359
1992	31.60723
1993	-18.55591
1994	-5.90746
1995	-13.60916
1996	-26.03195
1997	-24.00249
1998	-31.82894
1999	-13.89406
2000	0.66326
2001	3.60511
2002	-7.28041
2003	-23.53964
2004	-23.9284
2005	10.03942
2006	27.74689
2007	39.61724
2008	42.30938
2009	28.52745
2010	33.62345
2011	32.34592
2012	27.68611
2013	21.67612
2014	17.05525
2015	2.98805
2016	2.77798
2017	6.71276