Year including construction (constant 2010 US$) 1991 18885.0616323866 1992 19107.5814331736 1993 19296.8430173087 1994 18698.6968939044 1995 18708.4862226635 1996 18916.7758047419 1997 19811.237967257 1998 21332.2430030575 1999 22968.288308158 2000 24045.8981989486 2001 23466.94947943 2002 23523.8799034285 2003 22599.6179951218 2004 22963.8675894222 2005 22577.5055711109 2006 22318.9001043601 2007 22691.5016483123 2008 23154.577076136 2009 22613.9523586065 2010 22801.6948622549 2011 23367.8863086959 2012 21635.5304944329 2013 21061.4781648834 2014 21544.4072720298 2015 21723.6120803397 2016 24264.1071566151 2017 23928.8507062884