Year	constant 2015 US$
1991	17298.69998186442
1992	17374.46802932405
1993	17390.52162211328
1994	17030.490824194894
1995	16651.39767655135
1996	16697.672550503117
1997	16867.978697931372
1998	16815.027785965947
1999	16853.08018237338
2000	16997.240603305876
2001	16608.810737140004
2002	16405.498737730813
2003	16095.574501772851
2004	16298.547943449397
2005	16417.112861347276
2006	16626.336704274694
2007	17068.48352703205
2008	17279.562515768488
2009	16873.038870017004
2010	17504.415411029742
2011	17878.493039244564
2012	17847.76254189595
2013	18003.410650115995
2014	18007.53739238514
2015	17854.703309516677
2016	17755.41728266553
2017	17777.768858112013
2018	17766.528766161824
2019	17472.267329141527
2020	17815.65894962004
2021	17790.574388353427
2022	17512.606238343094