Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 50000 | Metric tons | NA |
| 2004 | 50000 | Metric tons | 0.00% |
| 2005 | 50000 | Metric tons | 0.00% |
| 2006 | 50000 | Metric tons | 0.00% |
| 2007 | 50000 | Metric tons | 0.00% |
| 2008 | 50000 | Metric tons | 0.00% |
| 2009 | 50300 | Metric tons | 0.60% |
| 2010 | 50300 | Metric tons | 0.00% |
| 2011 | 50300 | Metric tons | 0.00% |
| 2012 | 53000 | Metric tons | 5.37% |
| 2013 | 61480 | Metric tons | 16.00% |
