Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 180 | Thousand metric tons | NA |
| 2004 | 370 | Thousand metric tons | 105.56% |
| 2005 | 480 | Thousand metric tons | 29.73% |
| 2006 | 480 | Thousand metric tons | 0.00% |
| 2007 | 480 | Thousand metric tons | 0.00% |
