Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 122849 | Metric tons | NA |
| 2004 | 111887 | Metric tons | -8.92% |
| 2005 | 112781 | Metric tons | 0.80% |
| 2006 | 146942 | Metric tons | 30.29% |
| 2007 | 140000 | Metric tons | -4.72% |
| 2008 | 140000 | Metric tons | 0.00% |
| 2009 | 112000 | Metric tons | -20.00% |
| 2010 | 110000 | Metric tons | -1.79% |
| 2011 | 110000 | Metric tons | 0.00% |
| 2012 | 110000 | Metric tons | 0.00% |
| 2013 | 110000 | Metric tons | 0.00% |
