Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 18070 | Metric tons | NA |
| 2004 | 10470 | Metric tons | -42.06% |
| 2005 | 28500 | Metric tons | 172.21% |
| 2006 | 29000 | Metric tons | 1.75% |
| 2007 | 29000 | Metric tons | 0.00% |
| 2008 | 29000 | Metric tons | 0.00% |
| 2009 | 29000 | Metric tons | 0.00% |
| 2010 | 17500 | Metric tons | -39.66% |
| 2011 | 12400 | Metric tons | -29.14% |
| 2012 | 12000 | Metric tons | -3.23% |
