Year including construction (constant 2010 US$) 1991 6314.84914641017 1992 6942.76338677252 1993 6201.78326039706 1994 5186.94788860155 1995 4873.13768077755 1996 5764.0366904752 1997 5690.2115354649 1998 5451.12404446449 1999 5681.62471660517 2000 5255.23718076674 2001 4826.84130973203 2002 4428.70605835272 2003 3946.3666165839 2004 3753.62900206272 2005 3449.25848380228 2006 3496.18410551208 2007 3559.74772698975 2008 3627.96947969429 2009 3726.87534587336 2010 3663.61022857182 2011 3618.65973007277 2012 3633.43716019906 2013 3546.44885889028 2014 3627.89804468576 2015 3195.76401428088 2016 2967.85111458712 2017 3431.27178198154 2018 3478.05635435625