Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 2 | Metric tons | NA |
| 2003 | 3 | Metric tons | 50.00% |
| 2004 | 3 | Metric tons | 0.00% |
| 2005 | 3.57100009918213 | Metric tons | 19.03% |
| 2006 | 3.14199995994568 | Metric tons | -12.01% |
| 2007 | 3.29999995231628 | Metric tons | 5.03% |
| 2008 | 3.20000004768372 | Metric tons | -3.03% |
| 2009 | 3.92799997329712 | Metric tons | 22.75% |
| 2010 | 3.90000009536743 | Metric tons | -0.71% |
| 2011 | 4 | Metric tons | 2.56% |
| 2012 | 4 | Metric tons | 0.00% |
