Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 1770 | Metric tons | NA |
| 2003 | 1894 | Metric tons | 7.01 % |
| 2004 | 2158 | Metric tons | 13.94 % |
| 2005 | 4101 | Metric tons | 90.04 % |
| 2006 | 6233 | Metric tons | 51.99 % |
| 2007 | 10171 | Metric tons | 63.18 % |
| 2008 | 8790 | Metric tons | -13.58 % |
| 2009 | 8668 | Metric tons | -1.39 % |
