Year including construction (constant 2010 US$) 1991 7375.58471537703 1992 6943.86378664224 1993 6916.1676732307 1994 6927.20245610256 1995 7525.25358984255 1996 7653.48365716414 1997 8081.04520133851 1998 8328.27452182357 1999 8743.33428578841 2000 9339.15732815451 2001 9785.46609279794 2002 10378.3601559987 2003 11075.1313958705 2004 11673.9002860264 2005 12167.6834667396 2006 12874.4393563501 2007 13898.3889945833 2008 14620.9822166644 2009 15106.4953366951 2010 17338.7953592814 2011 18197.156520041 2012 18951.5635230398 2013 19591.5217892606 2014 20082.6642612918 2015 21041.7448813938 2016 21923.7065024238 2017 22647.9585057741 2018 23423.4486119631