Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 27500 | Metric tons | NA |
| 2003 | 27870 | Metric tons | 1.35% |
| 2004 | 31756 | Metric tons | 13.94% |
| 2005 | 34478 | Metric tons | 8.57% |
| 2006 | 19500 | Metric tons | -43.44% |
| 2007 | 15100 | Metric tons | -22.56% |
| 2008 | 7000 | Metric tons | -53.64% |
| 2009 | 3500 | Metric tons | -50.00% |
| 2010 | 12000 | Metric tons | 242.86% |
| 2011 | 10000 | Metric tons | -16.67% |
| 2012 | 10000 | Metric tons | 0.00% |
