Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 16 | Thousand metric tons | NA |
| 2005 | 13.3999996185303 | Thousand metric tons | -16.25 % |
| 2006 | 8 | Thousand metric tons | -40.30 % |
| 2007 | 40 | Thousand metric tons | 400.00 % |
