Year including construction (constant 2010 US$) 1991 5986.60376906603 1992 5945.46473224732 1993 5689.97086747778 1994 5380.44173630845 1995 5295.21560334609 1996 5409.18763855061 1997 5341.86113826743 1998 5314.6139990939 1999 5191.65586848121 2000 5007.66391259595 2001 5046.5685100651 2002 4996.73711248518 2003 5171.81224925598 2004 5248.05804106704 2005 5342.28765309582 2006 5253.42739283859 2007 5254.07512417073 2008 5360.26544372604 2009 5283.72710951959 2010 5378.89302269443 2011 5452.95085353964 2012 5352.19339963132 2013 5445.9837410852 2014 5570.73394162644 2015 5403.42222538279 2016 5370.24288080868 2017 5495.96796598227 2018 5619.95326005202