Year % change from 1990 1991 -10.1068859486988 1992 -19.1199984389162 1993 -17.7602488979591 1994 -18.6888599917155 1995 -19.1852592535395 1996 -10.599653987662 1997 -18.3083848851127 2004 -21.4782368384188 2005 -19.1011208258245 2006 -19.3262436620749 2007 -13.0024885217625 2008 -18.0457231746081 2009 -18.7677562869428 2010 -14.4534455584017 2011 -11.7443668808935 2012 -9.32588065246005