Year including construction (constant 2010 US$) 1991 17148.6644849854 1992 14404.8008821672 1993 13257.9562342226 1994 11595.9760567968 1995 11670.8542122467 1996 11435.3693601518 1997 12367.5215181331 1998 12681.0555378397 1999 12971.0266328191 2000 14026.7751546251 2001 14250.3630581344 2002 14690.2188251051 2003 15805.7678845274 2004 17289.7661974156 2005 18021.8006397553 2006 19303.7861880635 2007 20171.2463692734 2008 20675.2073495798 2009 19855.8354957848 2010 20701.7052847985 2011 22078.9062563271 2012 22221.5386549994 2013 22791.3418168665 2014 22470.0776819343 2015 22833.1793287901 2016 23431.8806448696 2017 24178.1914117318 2018 24740.4572063596