Year including construction (constant 2015 US$) 1991 17728.832263900473 1992 21147.156716092115 1993 21229.12543462627 1994 21491.62163057055 1995 20491.856404865957 1996 18795.37009547746 1997 19407.771812558767 1998 19336.132314453673 1999 20220.460778175697 2000 20578.12066908715 2001 22180.138024978056 2002 24658.81725181112 2003 22581.121669742697 2004 22024.534438358867 2005 22910.80171202244 2006 23717.2798493352 2007 22761.556265623552 2008 24135.109625741934 2009 23119.509247969694 2010 23764.903277889163 2011 24861.999368490793 2012 25518.53599243606 2013 25496.288881509692 2014 24337.984853096466 2015 22822.367838330825 2016 22272.819957690732 2017 22738.76652471756 2018 23530.42155784141 2019 24527.82405195927 2020 24977.80340425728 2021 24824.17070301722 2022 24792.69924336596