Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 333 | Thousand metric tons | NA |
| 2004 | 560 | Thousand metric tons | 68.17 % |
| 2005 | 689 | Thousand metric tons | 23.04 % |
| 2006 | 622 | Thousand metric tons | -9.72 % |
| 2007 | 23 | Thousand metric tons | -96.30 % |
