Year including construction (constant 2010 US$) 1991 18470.4204429321 1992 18849.9146665896 1993 21137.5493949821 1994 22663.8607253371 1995 24369.6989780224 1996 26424.4524554228 1997 28101.0661610004 1998 30729.9172272136 1999 34439.3531780992 2000 35839.3581248688 2001 37312.0322479851 2002 39405.1629942032 2003 41224.7509382989 2004 43877.1709649451 2005 46689.9416285793 2006 49988.0855356683 2007 53687.25590211 2008 55709.3059238694 2009 58338.1707594666 2010 62284.6961112444 2011 64300.1731773793 2012 65157.6635358255 2013 66582.7250867388 2014 66382.4431867214 2015 66029.9674269622 2016 68088.3396773367 2017 70137.2875322752 2018 71805.7100386197