Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 6595 | Metric tons | NA |
| 2003 | 3237 | Metric tons | -50.92 % |
| 2004 | 2979 | Metric tons | -7.97 % |
| 2005 | 8608 | Metric tons | 188.96 % |
| 2006 | 4841 | Metric tons | -43.76 % |
| 2007 | 3387 | Metric tons | -30.04 % |
| 2008 | 3179 | Metric tons | -6.14 % |
| 2009 | 557 | Metric tons | -82.48 % |
