Year % change from 1990 1991 1.69173732463883 1992 2.55017341017028 1993 3.85759082497024 1994 5.94844518677826 1995 7.13626938068954 1996 9.32644692594746 1997 13.1432949756658 1998 18.6901907207822 1999 19.6469364878917 2000 24.5553260536872 2001 26.175915546916 2002 27.6313042350189 2003 31.2474789140935 2004 26.4748985991377 2005 38.3055059502695 2006 31.3366670788241 2007 31.8647015541037 2008 32.0562534079 2009 29.295474308741 2010 27.6911008454632 2011 30.5505305978597 2012 31.512188230072