Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 25000 | Metric tons | NA |
| 2004 | 25000 | Metric tons | 0.00% |
| 2005 | 25767 | Metric tons | 3.07% |
| 2006 | 32507 | Metric tons | 26.16% |
| 2007 | 35234 | Metric tons | 8.39% |
| 2008 | 22890 | Metric tons | -35.03% |
| 2009 | 15350 | Metric tons | -32.94% |
| 2010 | 12798 | Metric tons | -16.63% |
| 2011 | 14466 | Metric tons | 13.03% |
| 2012 | 6900 | Metric tons | -52.30% |
| 2013 | 26820 | Metric tons | 288.70% |
