Year	Percent
1987	0.70423
1988	-4.08163
1989	-2.77778
1990	-5.33333
1991	-3.64583
1992	-30.63003
1993	-24.86141
1994	-51.35841
1995	-16.82489
1996	-19.04426
1997	-26.53246
1998	-20.64919
1999	-19.0407
2000	-16.67258
2001	-14.4072
2002	-13.17053
2003	-14.58449
2004	-16.62655
2005	-17.81944
2006	-24.15113
2007	-26.74487
2008	-29.78361
2009	-19.19465
2010	-17.81333
2011	-18.53165
2012	-19.6478
2013	-12.95215
2014	-17.52653
2015	-17.53227
2016	-15.72111
2017	-11.75733