Year including construction (constant 2015 US$) 1991 12904.47108880859 1992 14034.648858167779 1993 14971.742859065502 1994 15776.85906789652 1995 16119.256684636417 1996 17712.151106655176 1997 17635.209653987666 1998 17772.711456482648 1999 16479.161140614273 2000 16127.586904097736 2001 16073.54002589032 2002 16496.474434828182 2003 16772.717813195413 2004 17416.495250503805 2005 18162.36152669164 2006 18014.15761286072 2007 20578.005068196053 2008 21222.83840718777 2009 20987.660838162166 2010 21877.489725890962 2011 22061.54036802869 2012 21715.2661162692 2013 20780.648445009465 2014 18293.01127622753 2015 17241.15265247493 2016 18264.155084786835 2017 18490.174853428638 2018 18710.819829338925 2019 16670.60983685431 2020 18046.62990570937 2021 16352.569778251936 2022 16462.994706191323