Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2005 | 100 | Thousand metric tons | NA |
| 2006 | 100 | Thousand metric tons | 0.00% |
| 2007 | 100 | Thousand metric tons | 0.00% |
| 2008 | 105 | Thousand metric tons | 5.00% |
| 2009 | 110 | Thousand metric tons | 4.76% |
| 2010 | 80 | Thousand metric tons | -27.27% |
| 2011 | 70 | Thousand metric tons | -12.50% |
| 2012 | 150 | Thousand metric tons | 114.29% |
