Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 30 | Thousand metric tons | NA |
| 2003 | 200 | Thousand metric tons | 566.67% |
| 2004 | 170 | Thousand metric tons | -15.00% |
| 2005 | 150 | Thousand metric tons | -11.76% |
| 2006 | 150 | Thousand metric tons | 0.00% |
| 2007 | 270 | Thousand metric tons | 80.00% |
| 2008 | 160 | Thousand metric tons | -40.74% |
| 2009 | 140 | Thousand metric tons | -12.50% |
| 2010 | 160 | Thousand metric tons | 14.29% |
| 2011 | 150 | Thousand metric tons | -6.25% |
| 2012 | 150 | Thousand metric tons | 0.00% |
