Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 50 | Thousand metric tons | NA |
| 2004 | 50 | Thousand metric tons | 0.00% |
| 2005 | 119.831001281738 | Thousand metric tons | 139.66% |
| 2006 | 711.398986816406 | Thousand metric tons | 493.67% |
| 2007 | 671.335998535156 | Thousand metric tons | -5.63% |
| 2008 | 702.018005371094 | Thousand metric tons | 4.57% |
| 2009 | 524.752014160156 | Thousand metric tons | -25.25% |
| 2010 | 227.720993041992 | Thousand metric tons | -56.60% |
| 2011 | 118.977996826172 | Thousand metric tons | -47.75% |
| 2012 | 121.490997314453 | Thousand metric tons | 2.11% |
| 2013 | 113.575996398926 | Thousand metric tons | -6.51% |
