Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1729 | Metric tons | NA |
| 2004 | 1829 | Metric tons | 5.78 % |
| 2005 | 1664 | Metric tons | -9.02 % |
| 2006 | 1595 | Metric tons | -4.15 % |
| 2007 | 1600 | Metric tons | 0.31 % |
