Year	Percent
1990	-11.32976
1991	-19.37508
1992	-21.43525
1993	-13.53519
1994	-33.77275
1995	-38.25901
1996	-32.74956
1997	-38.0012
1998	-33.83641
1999	-29.0439
2000	-27.16801
2001	-20.68041
2002	-17.23032
2003	-17.88236
2004	-15.56755
2005	-14.42048
2006	-15.89122
2007	-19.96517
2008	-25.60866
2009	-27.52993
2010	-24.4871
2011	-23.59716
2012	-20.8333
2013	-19.83794
2014	-18.48141
2015	-12.13727
2016	-9.62187
2017	-12.34554