Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 152 | Thousand metric tons | NA |
| 2004 | 135 | Thousand metric tons | -11.18% |
| 2005 | 107 | Thousand metric tons | -20.74% |
| 2006 | 24 | Thousand metric tons | -77.57% |
| 2007 | 23 | Thousand metric tons | -4.17% |
