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 | 80000 | Metric tons | 0.00 % |
| 2004 | 110000 | Metric tons | 37.50 % |
| 2005 | 110000 | Metric tons | 0.00 % |
| 2006 | 100000 | Metric tons | -9.09 % |
| 2007 | 95000 | Metric tons | -5.00 % |
| 2008 | 95000 | Metric tons | 0.00 % |
