Year	constant 2010 US$
1991	22077.5911166887
1992	21580.5096711263
1993	20989.3599589828
1994	18493.0661577331
1995	18411.1233931269
1996	18692.880575531
1997	18889.5661112526
1998	17250.215104722
1999	15908.0569485756
2000	14942.0290485837
2001	15160.1750056135
2002	15170.5643439589
2003	15892.5386606739
2004	17148.3294067392
2005	16886.1649664211
2006	17164.7314889648
2007	17839.5197649423
2008	18167.8617423925
2009	19051.8205134477
2010	19499.6685772309
2011	19258.3229571197
2012	18347.0163153399
2013	20510.4471998025
2014	20930.7481591482
2015	21912.6206557597
2016	22391.7969144392
2017	21396.2581513506
2018	20302.2241677636