Year % change from 1990 1991 0.652648649186438 1992 -0.158353521334598 1993 3.66103392413291 1994 7.39867447324654 1995 14.805805521978 1996 19.5227506752824 1997 21.1750991989467 1998 24.3032030523263 1999 28.0716852296789 2000 28.347601731774 2001 29.2055296054759 2002 28.9728908720388 2003 29.3446485629625 2004 29.9513664002016 2005 30.6464637420181 2006 30.8338349243302 2007 31.9890694616478 2008 32.7350720715791 2009 33.9821682327913 2010 34.747239591365 2011 36.0947119872787 2012 37.4421843831923