Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 113 | Metric tons | NA |
| 2003 | 80 | Metric tons | -29.20% |
| 2004 | 71 | Metric tons | -11.25% |
| 2005 | 87.8740005493164 | Metric tons | 23.77% |
| 2006 | 86.9509963989258 | Metric tons | -1.05% |
| 2007 | 69.5879974365234 | Metric tons | -19.97% |
| 2008 | 75.1989974975586 | Metric tons | 8.06% |
| 2009 | 77.7799987792969 | Metric tons | 3.43% |
| 2010 | 79.3150024414063 | Metric tons | 1.97% |
| 2011 | 73.1800003051758 | Metric tons | -7.73% |
| 2012 | 66 | Metric tons | -9.81% |
