Year	US Dollars adjusted for inflation)
1991	4289.529
1992	4377.251
1993	4354.127
1994	4208.432
1995	4272.297
1996	4374.507
1997	4736.414
1998	4839.212
1999	4897.935
2000	5095.506
2001	5307.556
2002	5528.038
2003	5820.894
2004	5916.779
2005	6226.661
2006	6736.906
2007	7398.23
2008	7860.359
2009	8005.042
2010	8090.49
2011	7766.115
2012	7624.781
2013	7741.174
2014	7734.492
2015	7897.578
2016	8041.992
2017	8120.35
2018	8070.75
2019	8137.979
2020	8253.036
2021	8351.781
2022	8458.837