Year	US Dollars adjusted for inflation)
1988	15705124735.4972
1989	9038123668.25374
1990	11436223490.5073
1991	15804941958.3757
1992	16516154382.347
1993	17671949269.9987
1994	19086261532.9946
1995	20333538347.0688
1996	21377971332.2994
1997	20889102855.2594
1998	21639573809.2043
1999	21541530468.9803
2000	21831062969.9814
2001	22676199978.8416
2002	23450615963.9118
2003	24206305958.5895
2004	25637810960.50109
2005	26338308473.355
2006	26748258722.35469
2007	29249087911.2364
2008	32312600036.5717
2009	35561463093.95741
2010	38419626628.19241
2011	38772202696.5278
2012	39859470964.03929
2013	40910259905.4926
2014	41729660233.8068
2015	42069990678.188
2016	42911390491.68941
2017	43778557772.13809