Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 13 | Thousand metric tons | NA |
| 2004 | 13 | Thousand metric tons | 0.00% |
| 2005 | 12 | Thousand metric tons | -7.69% |
| 2006 | 12 | Thousand metric tons | 0.00% |
| 2007 | 12 | Thousand metric tons | 0.00% |
| 2008 | 12 | Thousand metric tons | 0.00% |
| 2009 | 180.300003051758 | Thousand metric tons | 1,402.50% |
| 2010 | 186.100006103516 | Thousand metric tons | 3.22% |
| 2011 | 190 | Thousand metric tons | 2.10% |
| 2012 | 180 | Thousand metric tons | -5.26% |
| 2013 | 190 | Thousand metric tons | 5.56% |
