Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 41 | Thousand metric tons | NA |
| 2004 | 33 | Thousand metric tons | -19.51% |
| 2005 | 38 | Thousand metric tons | 15.15% |
| 2006 | 53 | Thousand metric tons | 39.47% |
| 2007 | 19 | Thousand metric tons | -64.15% |
| 2008 | 31 | Thousand metric tons | 63.16% |
| 2010 | 32 | Thousand metric tons | 3.23% |
| 2011 | 46 | Thousand metric tons | 43.75% |
| 2012 | 45 | Thousand metric tons | -2.17% |
