Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1 | Thousand metric tons | NA |
| 2004 | 2 | Thousand metric tons | 100.00% |
| 2009 | 4.10400009155273 | Thousand metric tons | 105.20% |
| 2010 | 4.09999990463257 | Thousand metric tons | -0.10% |
| 2011 | 4.09999990463257 | Thousand metric tons | 0.00% |
| 2012 | 4.09999990463257 | Thousand metric tons | 0.00% |
