Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 529 | Metric tons | NA |
| 2004 | 532 | Metric tons | 0.57% |
| 2005 | 481 | Metric tons | -9.59% |
| 2006 | 416 | Metric tons | -13.51% |
| 2007 | 347 | Metric tons | -16.59% |
| 2008 | 371 | Metric tons | 6.92% |
| 2009 | 289 | Metric tons | -22.10% |
| 2010 | 357 | Metric tons | 23.53% |
| 2011 | 572 | Metric tons | 60.22% |
| 2012 | 684 | Metric tons | 19.58% |
| 2013 | 695 | Metric tons | 1.61% |
