Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 152383 | Metric tons | NA |
| 2004 | 192942 | Metric tons | 26.62% |
| 2005 | 188000 | Metric tons | -2.56% |
| 2006 | 188000 | Metric tons | 0.00% |
| 2007 | 188000 | Metric tons | 0.00% |
| 2008 | 336000 | Metric tons | 78.72% |
| 2009 | 97000 | Metric tons | -71.13% |
| 2010 | 140000 | Metric tons | 44.33% |
| 2011 | 165000 | Metric tons | 17.86% |
| 2012 | 165000 | Metric tons | 0.00% |
| 2013 | 165000 | Metric tons | 0.00% |
