Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 18000 | Metric tons | NA |
| 2003 | 14000 | Metric tons | -22.22% |
| 2004 | 18000 | Metric tons | 28.57% |
| 2005 | 20000 | Metric tons | 11.11% |
| 2006 | 21000 | Metric tons | 5.00% |
| 2007 | 21000 | Metric tons | 0.00% |
| 2008 | 21000 | Metric tons | 0.00% |
| 2009 | 21000 | Metric tons | 0.00% |
| 2010 | 21000 | Metric tons | 0.00% |
| 2011 | 21000 | Metric tons | 0.00% |
| 2012 | 21000 | Metric tons | 0.00% |
| 2013 | 23000 | Metric tons | 9.52% |
