Year	constant 2015 US$
1997	129.92639078948278
1998	80.81263082953092
1999	129.02787368250785
2000	381.1534922710303
2001	389.1649317769861
2002	390.67883541437214
2003	336.16018805985965
2004	389.8428224494602
2005	384.287395609969
2006	388.87729693669064
2007	379.99949684292216
2008	396.5130685880613
2009	373.3703843374497
2010	408.2682526099989
2011	472.71183173350045
2012	411.8174688615847
2013	396.1369408309349
2014	412.61991555985566
2015	454.01910534186123
2016	495.32308035595776
2017	514.2122544858772
2018	550.8318017134884
2019	593.4733933687247
2020	558.2252890422072
2021	578.3011338955516