Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 18012 | Metric tons | NA |
| 2003 | 16175 | Metric tons | -10.20% |
| 2004 | 11174 | Metric tons | -30.92% |
| 2005 | 10900 | Metric tons | -2.45% |
| 2006 | 6262 | Metric tons | -42.55% |
| 2007 | 8500 | Metric tons | 35.74% |
| 2008 | 7471 | Metric tons | -12.11% |
| 2011 | 3600 | Metric tons | -51.81% |
| 2012 | 4000 | Metric tons | 11.11% |
