Year % change from 1990 1991 -3.24462580364946 1992 -6.8174140584365 1993 -11.1864788490721 1994 -15.3995056114707 1995 -20.4415179122005 1996 -23.4920345535757 1997 -25.1172966277555 1998 -24.8942319550868 1999 -25.8974867689404 2000 -28.5640747910109 2001 -28.2552160134697 2002 -27.9200827913112 2003 -29.105650078019 2004 -27.8332162601277 2005 -24.6845726113044 2006 -22.5584874499311 2007 -20.2602778656572 2008 -17.7234534272064 2009 -14.6691832937429 2010 -11.8599625723217 2011 -11.3714688748661 2012 -10.8831896626726