Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 43.5 | Thousand metric tons | NA |
| 2004 | 44.5 | Thousand metric tons | 2.30% |
| 2005 | 45 | Thousand metric tons | 1.12% |
| 2006 | 12 | Thousand metric tons | -73.33% |
