2012 25.03 60.6 Billion
2011 24.71 58.3 Billion
2010 24.6 56.5 Billion
2009 23.6 53.4 Billion
2008 22.0 49.6 Billion
2007 20.9 46.1 Billion
2006 17.45 36.3 Billion
2005 16.4 32.0 Billion
2004 15.7 29.7 Billion
2003 10.5 23.1 Billion
2002 13.2 25.8 Billion
2001 12.7 24.2 Billion
2000 10.2 17.3 Billion