Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2004 | 7089 | Metric tons, gross weight | NA |
| 2007 | 19000 | Metric tons, gross weight | 168.02% |
| 2008 | 34350 | Metric tons, gross weight | 80.79% |
| 2009 | 23770 | Metric tons, gross weight | -30.80% |
| 2010 | 25000 | Metric tons, gross weight | 5.17% |
