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 | 1 | Thousand metric tons | 0.00% |
| 2005 | 0.5 | Thousand metric tons | -50.00% |
| 2006 | 0.600000023841858 | Thousand metric tons | 20.00% |
| 2007 | 0.600000023841858 | Thousand metric tons | 0.00% |
| 2008 | 1 | Thousand metric tons | 66.67% |
| 2009 | 0.699999988079071 | Thousand metric tons | -30.00% |
| 2010 | 0.699999988079071 | Thousand metric tons | 0.00% |
| 2011 | 0.699999988079071 | Thousand metric tons | 0.00% |
| 2012 | 0.699999988079071 | Thousand metric tons | 0.00% |
