Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 11500 | Metric tons | NA |
| 2004 | 7133 | Metric tons | -37.97% |
| 2005 | 15183 | Metric tons | 112.86% |
| 2006 | 44642 | Metric tons | 194.03% |
| 2007 | 87901 | Metric tons | 96.90% |
