Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 2906 | Metric tons | NA |
| 2004 | 3606 | Metric tons | 24.09% |
| 2005 | 17300 | Metric tons | 379.76% |
| 2006 | 23800 | Metric tons | 37.57% |
| 2007 | 27369 | Metric tons | 15.00% |
| 2008 | 45199 | Metric tons | 65.15% |
| 2009 | 27881 | Metric tons | -38.32% |
| 2010 | 52275 | Metric tons | 87.49% |
| 2011 | 86790 | Metric tons | 66.03% |
| 2012 | 76007 | Metric tons | -12.42% |
