Year % change from 1990 1991 -15.1569035571679 1992 -20.3152630097153 1993 -24.4437411075592 1994 -22.4367635852789 1995 -18.6426774778073 1996 -16.7050345784132 1997 -18.7895600807375 1998 -24.4655915110763 1999 -25.5831049567072 2000 -23.6000192044094 2001 -30.4577264433643 2002 -33.2055344138767 2003 -31.4321915829013 2004 -30.7658440718089 2005 -31.139653591485 2006 -32.9588822698463 2007 -33.138624287819 2008 -34.6773925608176 2009 -39.7114531494124 2010 -36.2606458608122 2011 -36.9010437811671 2012 -37.0629388169393