Year including construction (constant 2010 US$) 1993 18355.9902053604 1994 18684.1217391862 1995 20542.9814058614 1996 22138.3812830275 1997 21418.0297015343 1998 21170.9404987727 1999 22000.994646836 2000 23521.7326846942 2001 23625.3661328353 2002 24365.1323833172 2003 25114.7877672059 2004 27913.1309330666 2005 30154.4356483089 2006 33519.648656399 2007 34413.1388638221 2008 35916.2573240737 2009 34451.3030097561 2010 37378.8383063038 2011 38268.6049837211 2012 37334.4110364852 2013 36226.0541170529 2014 37014.8338146162 2015 38021.2248530535 2016 37550.0798443452 2017 39557.0076271274 2018 40259.2500238947