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 | 232 | Thousand metric tons | 28.89% |
| 2005 | 315 | Thousand metric tons | 35.78% |
| 2006 | 363 | Thousand metric tons | 15.24% |
| 2007 | 185 | Thousand metric tons | -49.04% |
