Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 7349 | Metric tons | NA |
| 2004 | 6005 | Metric tons | -18.29% |
| 2005 | 6000 | Metric tons | -0.08% |
| 2006 | 6010 | Metric tons | 0.17% |
| 2007 | 15450 | Metric tons | 157.07% |
| 2008 | 13063 | Metric tons | -15.45% |
