Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 57452 | Metric tons | NA |
| 2004 | 49046 | Metric tons | -14.63% |
| 2005 | 39545 | Metric tons | -19.37% |
| 2006 | 19151 | Metric tons | -51.57% |
| 2007 | 13311 | Metric tons | -30.49% |
| 2008 | 23276 | Metric tons | 74.86% |
| 2009 | 49847 | Metric tons | 114.16% |
| 2010 | 41385 | Metric tons | -16.98% |
| 2011 | 49081 | Metric tons | 18.60% |
| 2012 | 41500 | Metric tons | -15.45% |
