Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 86 | Thousand metric tons | NA |
| 2004 | 70 | Thousand metric tons | -18.60% |
| 2005 | 66 | Thousand metric tons | -5.71% |
| 2006 | 68 | Thousand metric tons | 3.03% |
| 2007 | 61 | Thousand metric tons | -10.29% |
