Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 300 | Thousand metric tons | NA |
| 2003 | 100 | Thousand metric tons | -66.67% |
| 2004 | 160 | Thousand metric tons | 60.00% |
| 2005 | 150 | Thousand metric tons | -6.25% |
| 2006 | 169 | Thousand metric tons | 12.67% |
| 2007 | 579 | Thousand metric tons | 242.60% |
| 2008 | 500 | Thousand metric tons | -13.64% |
| 2009 | 300 | Thousand metric tons | -40.00% |
| 2010 | 320 | Thousand metric tons | 6.67% |
| 2011 | 320 | Thousand metric tons | 0.00% |
| 2012 | 350 | Thousand metric tons | 9.38% |
| 2013 | 350 | Thousand metric tons | 0.00% |
