Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 40000 | Metric tons | NA |
| 2004 | 40000 | Metric tons | 0.00% |
| 2005 | 40000 | Metric tons | 0.00% |
| 2006 | 40644 | Metric tons | 1.61% |
| 2007 | 50459 | Metric tons | 24.15% |
| 2008 | 50000 | Metric tons | -0.91% |
| 2009 | 10581 | Metric tons | -78.84% |
| 2010 | 18073 | Metric tons | 70.81% |
| 2011 | 55000 | Metric tons | 204.32% |
| 2012 | 60000 | Metric tons | 9.09% |
| 2013 | 60000 | Metric tons | 0.00% |
