Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 36.7900009155273 | Thousand metric tons | NA |
| 2004 | 33.3400001525879 | Thousand metric tons | -9.38% |
| 2005 | 18 | Thousand metric tons | -46.01% |
| 2006 | 11 | Thousand metric tons | -38.89% |
| 2007 | 12 | Thousand metric tons | 9.09% |
| 2008 | 12 | Thousand metric tons | 0.00% |
| 2009 | 12 | Thousand metric tons | 0.00% |
