Year	US Dollars adjusted for inflation)
1991	18719.496
1992	15866.727
1993	14904.989
1994	13671.546
1995	13395.929
1996	13072.561
1997	13806.776
1998	13460.111
1999	13562.51
2000	14352.754
2001	15083.532
2002	15412.309
2003	16617.588
2004	17553.914
2005	18404.482
2006	19812.453
2007	20975.26
2008	21979.43
2009	20712.398
2010	21447.045
2011	22057.717
2012	22628.965
2013	23027.6
2014	23198.633
2015	22682.217
2016	22675.395
2017	23056.631
2018	23592.719
2019	24050.311
2020	24498.797
2021	24994.543
2022	25501.887