Year % change from 1990 1991 -1.0740611936274 1992 -2.57932650717211 1993 -4.06616910600181 1994 -3.70955550266758 1995 -5.23955298853069 1996 -5.80211909644743 1997 -6.8741607576689 1998 -7.87913709625598 1999 -9.58763535192015 2000 -10.6936066552882 2001 -11.5534774353743 2002 -12.3891696736388 2003 -13.1272348555855 2004 -14.1084555375647 2005 -15.761675850314 2006 -16.1965859065613 2007 -15.3045076448547 2008 -16.2155534566349 2009 -17.3360779167474 2010 -17.7215023323648 2011 -18.5331135997052 2012 -19.6633330982062