Year % change from 1990 1991 4.36152234573537 1992 10.7413106636153 1993 12.2864510745845 1994 13.190982498889 1995 14.1901390354285 1996 17.6096426919484 1997 18.6635185425919 1998 20.2243794194916 1999 22.2072743432927 2000 24.9329612823063 2001 27.6695316208103 2002 25.9442104849462 2003 25.4079007433966 2004 26.1884823401727 2005 28.6490375749367 2006 30.5182614373948 2007 34.0266461897521 2008 35.8027565232376 2009 36.6023840691217 2010 35.9599611825418 2011 37.3195607943672 2012 38.6791604061927