Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 2502 | Metric tons | NA |
| 2003 | 2767 | Metric tons | 10.59% |
| 2004 | 2383 | Metric tons | -13.88% |
| 2005 | 2570 | Metric tons | 7.85% |
| 2006 | 2581 | Metric tons | 0.43% |
| 2007 | 3000 | Metric tons | 16.23% |
| 2008 | 2827 | Metric tons | -5.77% |
| 2009 | 3572 | Metric tons | 26.35% |
| 2010 | 4700 | Metric tons | 31.58% |
| 2011 | 6000 | Metric tons | 27.66% |
| 2012 | 6300 | Metric tons | 5.00% |
