Year including construction (constant 2010 US$) 1995 17384.9406704794 1996 18472.6582662127 1997 20090.810639219 1998 20772.1778080146 1999 21657.7826570162 2000 23495.8270685692 2001 24807.7122360891 2002 26076.7370635646 2003 27190.952370848 2004 28451.4210356887 2005 30161.9230360428 2006 30355.7652735379 2007 29716.7930207181 2008 29514.1782271843 2009 28481.9189580326 2010 29591.3473787501 2011 29550.191241703 2012 28606.310675563 2013 28959.4485867948 2014 29273.9966865408 2015 29910.1442080219 2016 30989.1784308657 2017 31379.3733870392 2018 31230.2053045507