Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 79 | Metric tons | NA |
| 2003 | 95 | Metric tons | 20.25% |
| 2004 | 73 | Metric tons | -23.16% |
| 2005 | 137.559997558594 | Metric tons | 88.44% |
| 2006 | 167.339996337891 | Metric tons | 21.65% |
| 2007 | 198 | Metric tons | 18.32% |
| 2008 | 294 | Metric tons | 48.48% |
| 2009 | 351.600006103516 | Metric tons | 19.59% |
| 2010 | 363.519989013672 | Metric tons | 3.39% |
| 2011 | 246.5 | Metric tons | -32.19% |
| 2012 | 250 | Metric tons | 1.42% |
