Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 250000 | Metric tons | NA |
| 2003 | 340000 | Metric tons | 36.00% |
| 2004 | 442000 | Metric tons | 30.00% |
| 2005 | 470000 | Metric tons | 6.33% |
| 2006 | 520000 | Metric tons | 10.64% |
| 2007 | 625000 | Metric tons | 20.19% |
| 2008 | 559000 | Metric tons | -10.56% |
| 2009 | 501000 | Metric tons | -10.38% |
| 2010 | 654000 | Metric tons | 30.54% |
| 2011 | 661000 | Metric tons | 1.07% |
| 2012 | 698000 | Metric tons | 5.60% |
| 2013 | 770000 | Metric tons | 10.32% |
