Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 62000 | Metric tons | NA |
| 2003 | 102000 | Metric tons | 64.52% |
| 2004 | 118000 | Metric tons | 15.69% |
| 2005 | 126000 | Metric tons | 6.78% |
| 2006 | 126000 | Metric tons | 0.00% |
| 2007 | 146000 | Metric tons | 15.87% |
| 2008 | 110000 | Metric tons | -24.66% |
| 2009 | 97200 | Metric tons | -11.64% |
| 2010 | 115000 | Metric tons | 18.31% |
| 2011 | 120000 | Metric tons | 4.35% |
| 2012 | 110000 | Metric tons | -8.33% |
| 2013 | 110000 | Metric tons | 0.00% |
