Year including construction (constant 2010 US$) 1991 7708.22261572434 1992 7711.92462310275 1993 7277.47264868452 1994 6848.34300078497 1995 6646.33427841735 1996 6786.17063800039 1997 6689.19523674633 1998 6659.92846544864 1999 6405.84704052449 2000 6543.32424847619 2001 6725.74001453685 2002 6696.2014749014 2003 7056.5808410223 2004 7256.83829538555 2005 7537.94723401779 2006 7482.5591480365 2007 7334.57129266833 2008 7382.5137554786 2009 7122.16701630418 2010 7147.7511671618 2011 7294.96497931906 2012 7199.10853337268 2013 7096.27567469564 2014 7309.53518024773 2015 6917.27660711559 2016 6666.15120290594 2017 6683.79557473514 2018 6732.75246330322