Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1124 | Metric tons | NA |
| 2004 | 1293 | Metric tons | 15.04 % |
| 2005 | 1403 | Metric tons | 8.51 % |
| 2006 | 1585 | Metric tons | 12.97 % |
| 2007 | 1726 | Metric tons | 8.90 % |
| 2008 | 1813 | Metric tons | 5.04 % |
| 2009 | 1800 | Metric tons | -0.72 % |
