Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 71717 | Metric tons | NA |
| 2004 | 60924 | Metric tons | -15.05% |
| 2005 | 74920 | Metric tons | 22.97% |
| 2006 | 33100 | Metric tons | -55.82% |
| 2007 | 44897 | Metric tons | 35.64% |
| 2008 | 45000 | Metric tons | 0.23% |
