Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 30 | Thousand metric tons | NA |
| 2004 | 30 | Thousand metric tons | 0.00% |
| 2005 | 30 | Thousand metric tons | 0.00% |
| 2006 | 35 | Thousand metric tons | 16.67% |
| 2007 | 35 | Thousand metric tons | 0.00% |
| 2008 | 35 | Thousand metric tons | 0.00% |
| 2009 | 35 | Thousand metric tons | 0.00% |
| 2010 | 50 | Thousand metric tons | 42.86% |
| 2011 | 40 | Thousand metric tons | -20.00% |
| 2012 | 40 | Thousand metric tons | 0.00% |
| 2013 | 40 | Thousand metric tons | 0.00% |
