Year	current international $
1990	17930
1991	20920
1992	20340
1993	19600
1994	19980
1995	20130
1996	20820
1997	21130
1998	20620
1999	17630
2000	19680
2001	19220
2002	20710
2003	23450
2004	23980
2005	26720
2006	28950
2007	31340
2008	31100
2009	29330
2010	30250
2011	16110
2012	27650
2013	22160
2014	18640
2015	19360
2016	18180
2017	19410
2018	20220
2019	18290
2020	16470
2021	17930
2022	19580
2023	19670