Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 350 | Thousand metric tons | NA |
| 2004 | 350 | Thousand metric tons | 0.00% |
| 2005 | 350 | Thousand metric tons | 0.00% |
| 2006 | 350 | Thousand metric tons | 0.00% |
| 2007 | 360 | Thousand metric tons | 2.86% |
| 2008 | 360 | Thousand metric tons | 0.00% |
| 2009 | 1388.55700683594 | Thousand metric tons | 285.71% |
| 2010 | 1409.23901367188 | Thousand metric tons | 1.49% |
| 2011 | 1410 | Thousand metric tons | 0.05% |
| 2012 | 1410 | Thousand metric tons | 0.00% |
| 2013 | 1410 | Thousand metric tons | 0.00% |
