Year % change from 1990 1991 -6.62019378315577 1992 -17.5720110482704 1993 -26.2445745100618 1994 -32.5074531982989 1995 -36.189661975536 1996 -29.7278486562322 1997 -30.7417028365996 1998 -34.4255557016967 1999 -36.4812135560524 2000 -28.9923933535008 2001 -29.018150729975 2002 -31.1927309395414 2003 -31.8048796527686 2004 -32.3057784207988 2005 -33.9410978122671 2006 -34.2041518698759 2007 -33.9317813143934 2008 -34.9533079047744 2009 -35.4717436099785 2010 -34.0534438160375 2011 -35.1229599223459 2012 -34.773918660948