Year including construction (constant 2015 US$) 1991 15389.671845760435 1992 16309.058925920102 1993 16285.803964660125 1994 15847.420936086533 1995 16158.127624272134 1996 16321.207724080463 1997 17545.54722246886 1998 18222.87243544769 1999 19916.514182965206 2000 20108.980071645798 2001 19977.956609179357 2002 20128.240700386857 2003 19619.881316034236 2004 19701.490587770302 2005 19384.79158893633 2006 21208.590828086337 2007 21248.847268321166 2008 21427.13626307483 2009 20567.945347921424 2010 20364.44628395469 2011 19921.580631318677 2012 19876.10334760745 2013 18665.719976660763 2014 18685.204041487108 2015 18383.70285184038 2016 19510.908240670484 2017 19836.740154186304 2018 19511.57164834933 2019 18801.151184785966 2020 17974.12542212242 2021 18659.5997238355 2022 19144.247691690824