Year	constant 2010 US$
1991	5102.55391420471
1992	5343.458488012
1993	5205.74074582494
1994	5217.4190242224
1995	5111.91275609058
1996	5296.65428816951
1997	5198.79993313711
1998	4335.35137906047
1999	4160.81316159053
2000	4498.42924497184
2001	4673.65578487101
2002	5032.2624249464
2003	5452.88490462261
2004	5357.08447932558
2005	6056.63167428927
2006	6008.51299040897
2007	6169.10521507268
2008	6418.21070565343
2009	6486.02375365441
2010	6684.00624283301
2011	6969.07294023517
2012	7176.97016713981
2013	7382.03445609988
2014	7649.10399531637
2015	7895.36992907784
2016	7961.7236554159
2017	8038.44225585521
2018	8334.87452015666