Year	US Dollars adjusted for inflation)
1991	965.324
1992	911.507
1993	1054.754
1994	1297.91
1995	1347.307
1996	1447.133
1997	1531.298
1998	1516.817
1999	1468.704
2000	1374.354
2001	1434.799
2002	1421.09
2003	1324.177
2004	1289.141
2005	1276.415
2006	1230.507
2007	1220.245
2008	1076.646
2009	1099.378
2010	1102.347
2011	1176.817
2012	1229.882
2013	1238.506
2014	1272.391
2015	1306.906
2016	1325.045
2017	1338.807
2018	1358.121
2019	1377.169
2020	1399.716
2021	1422.728
2022	1448.179