Year including construction (constant 2010 US$) 1991 8770.40156593746 1992 8525.27746989883 1993 8465.18190920499 1994 8402.31639012884 1995 8562.92687645007 1996 8736.78883200403 1997 9073.8960353398 1998 9241.02799767662 1999 9486.71854837476 2000 9907.93615302848 2001 10068.829907782 2002 10399.4986972828 2003 10788.9055281662 2004 11249.4012104376 2005 11578.071993865 2006 12104.7213093555 2007 12732.5403306262 2008 13182.4097102806 2009 13296.8822346202 2010 14070.6682143242 2011 14600.9137540626 2012 14889.809549689 2013 15306.4004796887 2014 15598.6729526657 2015 15777.9358604673 2016 16419.0924148195 2017 16905.0609685634 2018 17329.7337603646