Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 88142 | Metric tons | NA |
| 2003 | 71694 | Metric tons | -18.66% |
| 2004 | 65772 | Metric tons | -8.26% |
| 2005 | 78404 | Metric tons | 19.21% |
| 2006 | 80933 | Metric tons | 3.23% |
| 2007 | 66137 | Metric tons | -18.28% |
| 2008 | 53228 | Metric tons | -19.52% |
| 2009 | 46078 | Metric tons | -13.43% |
| 2010 | 43258 | Metric tons | -6.12% |
| 2011 | 42000 | Metric tons | -2.91% |
| 2012 | 41000 | Metric tons | -2.38% |
| 2013 | 95200 | Metric tons | 132.20% |
