Year including construction (constant 2010 US$) 1991 15620.6559322386 1992 16944.2969813148 1993 17368.9722961508 1994 17434.0400865908 1995 17582.7625399081 1996 17199.7908281256 1997 17249.9129585121 1998 17733.5390412528 1999 17892.470021104 2000 18337.6587109227 2001 17985.9963606239 2002 18821.4329468801 2003 19108.9127347506 2004 19982.3796041974 2005 19848.0729107437 2006 20378.5425219964 2007 20278.6676307942 2008 20791.7423807664 2009 20885.7688092203 2010 21859.0479772118 2011 24177.7394656008 2012 24562.707517277 2013 25474.6110791726 2014 23918.9332454967 2015 22182.7926301946 2016 23997.0127064038 2017 23872.1305280124 2018 24454.8635500338