Year including construction (constant 2010 US$) 1991 4090.77884069997 1992 3924.51637630488 1993 3868.97903404365 1994 3725.06624163354 1995 3762.63928393753 1996 3850.32292278199 1997 3831.00787527399 1998 3831.60056357036 1999 3876.28830663148 2000 3604.23192393325 2001 3582.09812900596 2002 3598.50194344633 2003 3658.11519200615 2004 3689.7704039143 2005 3720.04383697757 2006 3706.08225400326 2007 3844.29838162969 2008 4095.06560388064 2009 4130.11410507175 2010 4275.50278504261 2011 4308.08680446211 2012 4204.30382723456 2013 4422.76309049704 2014 4516.59981390932 2015 4487.9301694994 2016 4602.56880216232 2017 4793.02685069296 2018 4873.96016207186