Year including construction (constant 2010 US$) 1991 26347.9219819147 1992 25856.7209089893 1993 26386.6839381586 1994 26611.6323065954 1995 27633.3581441475 1996 27368.7334546795 1997 27727.8359983176 1998 26807.0199862347 1999 25821.9322349748 2000 24703.1158591084 2001 23048.3177669809 2002 22110.5647163966 2003 21762.8098874363 2004 19882.9216403555 2005 20365.7951452136 2006 19899.3651754767 2007 17771.6609469136 2008 17982.1451269198 2009 18616.151477292 2010 17800.9290102812 2011 19696.6967248381 2012 19973.5630760091 2013 20388.7785134448 2014 19572.916596924 2015 19219.766640604 2016 20392.4010906604 2017 19860.1407039865 2018 19795.7636350634