Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 3387 | Metric tons | NA |
| 2004 | 3400 | Metric tons | 0.38% |
| 2005 | 3000 | Metric tons | -11.76% |
| 2006 | 5756 | Metric tons | 91.87% |
| 2007 | 9593 | Metric tons | 66.66% |
| 2008 | 10000 | Metric tons | 4.24% |
| 2009 | 3171 | Metric tons | -68.29% |
| 2010 | 3437 | Metric tons | 8.39% |
| 2011 | 3500 | Metric tons | 1.83% |
| 2012 | 3600 | Metric tons | 2.86% |
| 2013 | 3700 | Metric tons | 2.78% |
