Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 23000 | Metric tons | NA |
| 2004 | 39400 | Metric tons | 71.30 % |
| 2005 | 32500 | Metric tons | -17.51 % |
| 2006 | 26100 | Metric tons | -19.69 % |
| 2007 | 22000 | Metric tons | -15.71 % |
| 2008 | 22000 | Metric tons | 0.00 % |
| 2009 | 7000 | Metric tons | -68.18 % |
