Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 35 | Thousand metric tons | NA |
| 2004 | 35 | Thousand metric tons | 0.00% |
| 2005 | 35.0999984741211 | Thousand metric tons | 0.29% |
| 2006 | 35.0999984741211 | Thousand metric tons | 0.00% |
| 2007 | 21.6030006408691 | Thousand metric tons | -38.45% |
| 2008 | 12.206000328064 | Thousand metric tons | -43.50% |
| 2009 | 9.94600009918213 | Thousand metric tons | -18.52% |
| 2010 | 10.5 | Thousand metric tons | 5.57% |
| 2011 | 15 | Thousand metric tons | 42.86% |
| 2012 | 80.7389984130859 | Thousand metric tons | 438.26% |
