Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 33172 | Metric tons | NA |
| 2003 | 12131 | Metric tons | -63.43% |
| 2004 | 13710 | Metric tons | 13.02% |
| 2005 | 37499 | Metric tons | 173.52% |
| 2006 | 30000 | Metric tons | -20.00% |
| 2007 | 30000 | Metric tons | 0.00% |
| 2008 | 25000 | Metric tons | -16.67% |
| 2009 | 50000 | Metric tons | 100.00% |
| 2010 | 47000 | Metric tons | -6.00% |
| 2011 | 48000 | Metric tons | 2.13% |
| 2012 | 53000 | Metric tons | 10.42% |
| 2013 | 50000 | Metric tons | -5.66% |
