Year constant 2015 US$ 1990 19710.892006572223 1991 20069.757474729133 1992 19177.783442395965 1993 18102.881036200466 1994 18462.409794161802 1995 18759.508613928647 1996 19597.22767498709 1997 20659.63006883703 1998 22847.701790089763 1999 24216.32278137063 2000 24830.285607612685 2001 23818.95290027429 2002 23436.188731382725 2003 24656.621385455917 2004 26188.31576212242 2005 28783.759550456994 2006 29198.305525347507 2007 30352.7894232419 2008 27798.616269755963 2009 24241.22532881895 2010 24212.59026642472 2011 24656.22090198459 2012 24971.657869720617 2013 25000.835720985408 2014 25442.590958545432 2015 26308.39785045729 2016 27692.851477938802 2017 29205.50279144784 2018 29807.057630173975 2019 29667.68894577518 2020 28283.270289642816 2021 29756.176227328124 2022 31425.3775658451 2023 30656.97847468251