Year including construction (constant 2015 US$) 1991 6649.632503545337 1992 6913.069949269344 1993 6672.153527581514 1994 6565.604093219587 1995 6717.741569580743 1996 6855.354179263887 1997 6941.962241762743 1998 7235.673454599494 1999 7116.904002521502 2000 7455.641603019186 2001 7584.547097798209 2002 7485.242821764589 2003 7059.925667997466 2004 6817.149170135661 2005 6329.242087716546 2006 5975.795560355369 2007 6080.134329688292 2008 5818.9784544666145 2009 5928.681880807691 2010 5802.5109220854465 2011 6100.644013326136 2012 5996.203960537288 2013 6081.50669174686 2014 6136.3941917407865 2015 6577.564422916352 2016 6138.146719953953 2017 6487.873981773545 2018 5882.341033331445 2019 5414.8816041789905 2020 5122.233025669335 2021 5076.827591691922 2022 5009.155838627039