Year % 1985 -17.885479994926435 1986 -8.907682262303165 1987 7.948365223586042 1988 18.080588334567214 1989 11.514995250767267 1990 12.982206210834066 1991 -45.94845708137223 1992 24.325612223633584 1993 19.916823553236753 1994 20.45012127281418 1995 20.27487219296455 1996 15.808486264458269 1997 33.466792257617094 1998 18.938273306660406 1999 27.09540133606935 2000 21.310565847745526 2001 21.800959615058495 2002 12.327647118311297 2003 14.561801970094614 2004 -29.708059235565614 2005 29.585760793675878 2006 28.080845303774506 2007 22.508146507746616 2008 23.931643524605388 2009 21.515628628387688 2010 20.21468541187548 2011 22.40355814853612 2012 23.26043865363287 2013 20.83094149283598 2014 22.134678727318338 2017 24.131896309085842 2018 19.680120427551135 2019 20.468086581481643 2020 25.258395643986855 2021 11.284817991327534