Year % change from 1990 1991 -1.06199737637597 1992 -2.05422156314757 1993 -2.99245232799102 1994 -3.7789691819236 1995 -4.15796878267648 1996 -4.49238578680203 1997 -4.76187760223578 1998 -96.2622863552539 1999 -93.3840015969885 2000 -91.2878571835967 2001 -91.0416547843114 2002 -91.2752220669595 2003 -89.9126856023878 2004 -89.9246009429837 2005 -89.0427815167589 2006 -88.5013555390787 2007 -87.8769567862507 2008 -87.465250480047 2009 -88.9408543888667 2010 -87.7459647521816 2011 -87.7459647521821 2012 -87.7459647521816