Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 6905 | Metric tons | NA |
| 2004 | 3435 | Metric tons | -50.25% |
| 2005 | 5832 | Metric tons | 69.78% |
| 2006 | 6648 | Metric tons | 13.99% |
| 2007 | 9043 | Metric tons | 36.03% |
| 2008 | 9040 | Metric tons | -0.03% |
| 2009 | 6601 | Metric tons | -26.98% |
| 2010 | 9000 | Metric tons | 36.34% |
| 2011 | 1655 | Metric tons | -81.61% |
| 2012 | 6935 | Metric tons | 319.03% |
| 2013 | 7000 | Metric tons | 0.94% |
