Year including construction (constant 2010 US$) 1991 6606.04820582573 1992 7017.21602652104 1993 7320.16892351041 1994 7606.70726477733 1995 7737.27408214389 1996 8503.67807923841 1997 8898.48630495685 1998 9197.93818533422 1999 9319.55934737618 2000 9703.06327071788 2001 10740.7010169188 2002 10292.7360546126 2003 11397.7115964417 2004 11605.5252998567 2005 11532.3608174937 2006 12032.2061464566 2007 12702.6441133037 2008 13068.2649970374 2009 14279.4410072686 2010 14895.0706183699 2011 15236.3225105728 2012 15254.6349776374 2013 15140.8677760772 2014 15043.1528948369 2015 14833.8450269786 2016 14993.3499725321 2017 15384.1770638499 2018 15791.0457229236