Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 71 | Thousand metric tons | NA |
| 2004 | 71 | Thousand metric tons | 0.00% |
| 2005 | 25 | Thousand metric tons | -64.79% |
| 2006 | 16 | Thousand metric tons | -36.00% |
| 2007 | 66 | Thousand metric tons | 312.50% |
| 2008 | 35 | Thousand metric tons | -46.97% |
| 2009 | 13 | Thousand metric tons | -62.86% |
| 2010 | 5 | Thousand metric tons | -61.54% |
| 2011 | 11 | Thousand metric tons | 120.00% |
| 2012 | 14 | Thousand metric tons | 27.27% |
| 2013 | 11 | Thousand metric tons | -21.43% |
