Year including construction (constant 2010 US$) 1991 30059.62297945 1992 26078.2014418303 1993 26688.8227858754 1994 26225.3067799248 1995 26331.4841968042 1996 26405.9573310025 1997 28198.7745391544 1998 26614.4950530192 1999 26678.3578019063 2000 26123.2895475785 2001 25996.7874642206 2002 27234.5517257522 2003 27158.618038895 2004 27085.2469797785 2005 28754.4370445835 2006 28876.6353753326 2007 28407.7992071564 2008 27238.4364415599 2009 24242.1735365781 2010 23433.203621312 2011 23875.1720567735 2012 22865.222069955 2013 21518.376125806 2014 22088.1817072499 2015 21674.6758910219 2016 21627.5254706887