Year % change from 1990 1991 -7.51010125446634 1992 -18.182507136689 1993 -18.7535919216207 1994 -19.4809950032926 1995 -20.6359423422773 1996 -17.2612325457622 1997 -19.2631640237067 1998 -20.1568246920829 1999 -19.8603722477311 2000 -22.6239614897618 2001 -22.1246257389887 2002 -23.5056149402618 2003 -21.078973173758 2004 -22.1586809282903 2005 -22.5607152741957 2006 -22.97395197691 2007 -25.8538320596226 2008 -26.6251082496927 2009 -32.5365187923927 2010 -32.0868754013234 2011 -33.9994611609901 2012 -35.431108707449