Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 146000 | Metric tons | NA |
| 2004 | 225000 | Metric tons | 54.11% |
| 2005 | 181000 | Metric tons | -19.56% |
| 2006 | 134000 | Metric tons | -25.97% |
| 2007 | 99000 | Metric tons | -26.12% |
| 2008 | 178000 | Metric tons | 79.80% |
| 2009 | 108000 | Metric tons | -39.33% |
| 2010 | 100000 | Metric tons | -7.41% |
| 2011 | 54000 | Metric tons | -46.00% |
| 2012 | 78000 | Metric tons | 44.44% |
| 2013 | 78000 | Metric tons | 0.00% |
