Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 12046 | Metric tons | NA |
| 2003 | 9755 | Metric tons | -19.02 % |
| 2004 | 12100 | Metric tons | 24.04 % |
| 2005 | 8924 | Metric tons | -26.25 % |
| 2006 | 8585 | Metric tons | -3.80 % |
| 2007 | 7991 | Metric tons | -6.92 % |
| 2008 | 8000 | Metric tons | 0.11 % |
| 2009 | 8000 | Metric tons | 0.00 % |
