Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 375 | Metric tons | NA |
| 2004 | 356 | Metric tons | -5.07% |
| 2005 | 408 | Metric tons | 14.61% |
| 2006 | 373 | Metric tons | -8.58% |
| 2007 | 421 | Metric tons | 12.87% |
| 2008 | 603 | Metric tons | 43.23% |
| 2009 | 534 | Metric tons | -11.44% |
| 2010 | 451 | Metric tons | -15.54% |
| 2011 | 526 | Metric tons | 16.63% |
| 2012 | 370 | Metric tons | -29.66% |
| 2013 | 400 | Metric tons | 8.11% |
