Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 60 | Thousand metric tons | NA |
| 2004 | 60 | Thousand metric tons | 0.00% |
| 2005 | 60 | Thousand metric tons | 0.00% |
| 2006 | 60 | Thousand metric tons | 0.00% |
| 2007 | 60 | Thousand metric tons | 0.00% |
| 2008 | 243 | Thousand metric tons | 305.00% |
| 2009 | 482.468994140625 | Thousand metric tons | 98.55% |
| 2010 | 620.934997558594 | Thousand metric tons | 28.70% |
| 2011 | 684.734008789063 | Thousand metric tons | 10.27% |
| 2012 | 749.539001464844 | Thousand metric tons | 9.46% |
