Year US Dollars adjusted for inflation) 1991 2869.697 1992 2817.257 1993 2767.708 1994 2754.108 1995 2813.127 1996 2895.011 1997 3041.778 1998 2991.237 1999 1956.931 2000 2425.334 2001 2807.873 2002 2598.596 2003 2512.476 2004 2506.475 2005 2664.477 2006 2478.83 2007 2765.449 2008 3164.172 2009 3575.008 2010 3894.962 2011 4174.657 2012 4346.076 2013 4375.208 2014 4542.127 2015 4647.32 2016 4797.19 2017 4795.307 2018 4797.805 2019 4794.199 2020 4818.099 2021 4825.562 2022 4836.582