Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 41 | Thousand metric tons | NA |
| 2004 | 58 | Thousand metric tons | 41.46% |
| 2005 | 64 | Thousand metric tons | 10.34% |
| 2006 | 57 | Thousand metric tons | -10.94% |
| 2007 | 71 | Thousand metric tons | 24.56% |
