Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 3 | Thousand metric tons | NA |
| 2003 | 2 | Thousand metric tons | -33.33% |
| 2004 | 3 | Thousand metric tons | 50.00% |
| 2005 | 2 | Thousand metric tons | -33.33% |
| 2006 | 2 | Thousand metric tons | 0.00% |
| 2007 | 2 | Thousand metric tons | 0.00% |
| 2008 | 2 | Thousand metric tons | 0.00% |
| 2009 | 46.4000015258789 | Thousand metric tons | 2,220.00% |
| 2010 | 63.0999984741211 | Thousand metric tons | 35.99% |
| 2011 | 62 | Thousand metric tons | -1.74% |
| 2012 | 57.25 | Thousand metric tons | -7.66% |
| 2013 | 57.25 | Thousand metric tons | 0.00% |
