Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 80000 | Metric tons | NA |
| 2003 | 78000 | Metric tons | -2.50% |
| 2004 | 54000 | Metric tons | -30.77% |
| 2005 | 50000 | Metric tons | -7.41% |
| 2006 | 65000 | Metric tons | 30.00% |
| 2007 | 16300 | Metric tons | -74.92% |
| 2008 | 2000 | Metric tons | -87.73% |
