Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 126 | Metric tons | NA |
| 2003 | 134 | Metric tons | 6.35% |
| 2004 | 172 | Metric tons | 28.36% |
| 2005 | 263.765991210938 | Metric tons | 53.35% |
| 2006 | 245.123992919922 | Metric tons | -7.07% |
| 2007 | 255.567001342773 | Metric tons | 4.26% |
| 2008 | 355.596008300781 | Metric tons | 39.14% |
| 2009 | 532.822998046875 | Metric tons | 49.84% |
| 2010 | 723.237976074219 | Metric tons | 35.74% |
| 2011 | 747.448974609375 | Metric tons | 3.35% |
| 2012 | 800 | Metric tons | 7.03% |
