Year including construction (constant 2010 US$) 1991 3880.84094188093 1992 3760.98154274269 1993 3728.38917670766 1994 3645.28825485973 1995 3674.36454605191 1996 3756.442731294 1997 3715.91404301475 1998 3722.12188168772 1999 3759.71385988984 2000 3506.90504538118 2001 3476.67222231425 2002 4383.07432375142 2003 4399.67922477749 2004 4545.92048029531 2005 4742.64447860891 2006 4852.16215370563 2007 5144.94962777211 2008 5354.69413250765 2009 5271.33885034315 2010 5369.39862059961 2011 5287.08435421722 2012 5230.16554273349 2013 5385.30348515774 2014 5393.26344412412 2015 5411.49911502456 2016 5473.94712815041 2017 5576.29953258899 2018 4676.53283000816