Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 9.3149995803833 | Thousand metric tons | NA |
| 2004 | 9.57800006866455 | Thousand metric tons | 2.82% |
| 2005 | 120 | Thousand metric tons | 1,152.87% |
| 2006 | 190.800003051758 | Thousand metric tons | 59.00% |
| 2007 | 233.990997314453 | Thousand metric tons | 22.64% |
| 2008 | 349.890991210938 | Thousand metric tons | 49.53% |
| 2009 | 187.220993041992 | Thousand metric tons | -46.49% |
| 2010 | 292.855010986328 | Thousand metric tons | 56.42% |
| 2012 | 104.071998596191 | Thousand metric tons | -64.46% |
| 2013 | 224 | Thousand metric tons | 115.24% |
