Year	current US$
1996	21563100
1997	23462600
1998	21915200
1999	23271000
2000	23281000
2001	25481000
2002	31319000
2003	34407000
2004	37858000
2005	39025000
2010	18981000
2011	19755000
2012	17948000
2013	21226000
2014	13541000
2015	15165000
2016	21184000
2017	19620000
2018	16980000
2019	16402999.999999998
2020	17596000
2021	21213000
2022	17209000