Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 103174 | Metric tons | NA |
| 2004 | 156760 | Metric tons | 51.94% |
| 2005 | 105000 | Metric tons | -33.02% |
| 2006 | 154746 | Metric tons | 47.38% |
| 2007 | 155000 | Metric tons | 0.16% |
| 2008 | 155000 | Metric tons | 0.00% |
| 2009 | 140000 | Metric tons | -9.68% |
| 2010 | 157001 | Metric tons | 12.14% |
| 2011 | 110271 | Metric tons | -29.76% |
| 2012 | 115000 | Metric tons | 4.29% |
| 2013 | 115000 | Metric tons | 0.00% |
