Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 529 | Metric tons | NA |
| 2004 | 532 | Metric tons | 0.57 % |
| 2005 | 481 | Metric tons | -9.59 % |
| 2006 | 416 | Metric tons | -13.51 % |
| 2007 | 347 | Metric tons | -16.59 % |
| 2008 | 371 | Metric tons | 6.92 % |
| 2009 | 375 | Metric tons | 1.08 % |
