Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 213660 | Thousand metric tons | NA |
| 2004 | 251850 | Thousand metric tons | 17.87% |
| 2005 | 343750 | Thousand metric tons | 36.49% |
| 2006 | 412450 | Thousand metric tons | 19.99% |
| 2007 | 476520 | Thousand metric tons | 15.53% |
| 2008 | 470670 | Thousand metric tons | -1.23% |
| 2009 | 552830 | Thousand metric tons | 17.46% |
| 2010 | 597330 | Thousand metric tons | 8.05% |
| 2011 | 640510 | Thousand metric tons | 7.23% |
| 2012 | 657900 | Thousand metric tons | 2.72% |
