Year	constant 2010 US$
1991	29926.1925419825
1992	30017.6806870687
1993	29674.1343866822
1994	29085.1220924866
1995	28883.5264239253
1996	27690.0604581342
1997	28651.3440551477
1998	27141.1522338439
1999	26383.2033968025
2000	26005.4139652217
2001	26817.500483769
2002	26867.9454533794
2003	26606.9355953907
2004	26389.1516445773
2005	26718.9799040328
2006	28134.2955159286
2007	30120.3492838382
2008	30446.5856481681
2009	30680.1807737591
2010	29419.4018029366
2011	30295.9736759475
2012	31515.4762707422
2013	32550.7457935536
2014	32314.9766210867
2015	31305.9905524097
2016	32074.5672853081
2017	32129.6159533537
2018	31900.4351798508