Year % 1980 5.117486184224884 1981 4.414200729734231 1982 1.7386796544083716 1983 4.4232584944232 1984 0.9804055269677655 1985 1.591977310928618 1986 4.418923375812217 1987 1.392216642784893 1988 6.278804872917099 1989 1.8743728369017016 1990 7.168106837337504 1991 -22.213715382313307 1992 9.543413358177023 1993 5.06684157579013 1994 6.367719543559474 1995 17.00805781993948 1996 19.775689400552107 1997 8.853672923965913 1998 5.950435648958675 1999 22.1671078554616 2000 18.083177845835863 2001 15.755375370611318 2002 13.386343910532599 2003 15.805564985853286 2004 9.07038274530279 2005 7.416376435742212 2006 8.685112483077852 2007 13.411392435212832 2008 8.686177855625404 2009 19.930464210548706 2010 -4.367361729868626 2011 -0.46599403467414663 2012 16.469090593045205 2013 11.974614793110053 2014 32.767950839880996 2015 22.891296400070722 2016 5.206243580168389 2017 15.175688117304738