Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2005 | 1.63999998569489 | Thousand metric tons | NA |
| 2006 | 5.3730001449585 | Thousand metric tons | 227.62% |
| 2007 | 5.00299978256226 | Thousand metric tons | -6.89% |
| 2008 | 5 | Thousand metric tons | -0.06% |
| 2009 | 5 | Thousand metric tons | 0.00% |
