Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 194463 | Metric tons | NA |
| 2004 | 188027 | Metric tons | -3.31% |
| 2005 | 91724 | Metric tons | -51.22% |
| 2006 | 41219 | Metric tons | -55.06% |
| 2007 | 41000 | Metric tons | -0.53% |
| 2008 | 54405 | Metric tons | 32.70% |
| 2009 | 51395 | Metric tons | -5.53% |
| 2010 | 31779 | Metric tons | -38.17% |
| 2011 | 31779 | Metric tons | 0.00% |
| 2012 | 30750 | Metric tons | -3.24% |
| 2013 | 30700 | Metric tons | -0.16% |
