Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 182 | Thousand metric tons | NA |
| 2004 | 125 | Thousand metric tons | -31.32% |
| 2005 | 129 | Thousand metric tons | 3.20% |
| 2006 | 38 | Thousand metric tons | -70.54% |
| 2007 | 45 | Thousand metric tons | 18.42% |
