Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 4 | Thousand metric tons | NA |
| 2003 | 4 | Thousand metric tons | 0.00% |
| 2004 | 8.83699989318848 | Thousand metric tons | 120.93% |
| 2005 | 28.242000579834 | Thousand metric tons | 219.59% |
| 2006 | 35.0340003967285 | Thousand metric tons | 24.05% |
| 2007 | 22.0370006561279 | Thousand metric tons | -37.10% |
| 2008 | 23 | Thousand metric tons | 4.37% |
| 2009 | 45.6300010681152 | Thousand metric tons | 98.39% |
| 2010 | 49.2000007629395 | Thousand metric tons | 7.82% |
| 2011 | 100.800003051758 | Thousand metric tons | 104.88% |
| 2012 | 150.5 | Thousand metric tons | 49.31% |
| 2013 | 152 | Thousand metric tons | 1.00% |
