Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 115000 | Metric tons | NA |
| 2004 | 107829 | Metric tons | -6.24% |
| 2005 | 100000 | Metric tons | -7.26% |
| 2006 | 100000 | Metric tons | 0.00% |
| 2007 | 100000 | Metric tons | 0.00% |
| 2008 | 100000 | Metric tons | 0.00% |
| 2009 | 47218 | Metric tons | -52.78% |
| 2010 | 51897 | Metric tons | 9.91% |
| 2011 | 11957 | Metric tons | -76.96% |
| 2012 | 8857 | Metric tons | -25.93% |
| 2013 | 9000 | Metric tons | 1.61% |
