Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 23101 | Metric tons | NA |
| 2004 | 39797 | Metric tons | 72.27% |
| 2005 | 42791 | Metric tons | 7.52% |
| 2006 | 45000 | Metric tons | 5.16% |
| 2007 | 62015 | Metric tons | 37.81% |
| 2008 | 56077 | Metric tons | -9.58% |
| 2009 | 64381 | Metric tons | 14.81% |
| 2010 | 26302 | Metric tons | -59.15% |
| 2011 | 8562 | Metric tons | -67.45% |
| 2012 | 16062 | Metric tons | 87.60% |
| 2013 | 15000 | Metric tons | -6.61% |
