Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 39575 | Metric tons | NA |
| 2004 | 25204 | Metric tons | -36.31% |
| 2005 | 37732 | Metric tons | 49.71% |
| 2006 | 38000 | Metric tons | 0.71% |
| 2007 | 39000 | Metric tons | 2.63% |
