Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 625 | Thousand metric tons | NA |
| 2004 | 943 | Thousand metric tons | 50.88% |
| 2005 | 207 | Thousand metric tons | -78.05% |
| 2006 | 500 | Thousand metric tons | 141.55% |
| 2007 | 500 | Thousand metric tons | 0.00% |
| 2008 | 500 | Thousand metric tons | 0.00% |
| 2009 | 674.452026367188 | Thousand metric tons | 34.89% |
| 2010 | 459.235992431641 | Thousand metric tons | -31.91% |
| 2011 | 500 | Thousand metric tons | 8.88% |
| 2012 | 117.78800201416 | Thousand metric tons | -76.44% |
| 2013 | 7.61999988555908 | Thousand metric tons | -93.53% |
