Year	constant 2010 US$
1991	21556.0167303259
1992	21052.7059809406
1993	20904.7412187817
1994	21048.900774087
1995	20949.1140795205
1996	21556.2749724379
1997	21486.0065580987
1998	21187.5496485868
1999	20916.1536817118
2000	20927.1978751272
2001	20643.8232980989
2002	20747.78750275
2003	20522.9705764862
2004	20901.3538705697
2005	21115.6644651276
2006	21202.0141921497
2007	22007.1059820103
2008	22468.7005743104
2009	22602.0259220749
2010	23378.4539322004
2011	23732.1559632293
2012	22867.9771456497
2013	23002.5713578629
2014	22584.3225862018
2015	21868.7907901237
2016	21563.0935949883
2017	21213.3203070534
2018	21149.8495247526