Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 723000 | Metric tons | NA |
| 2004 | 1100000 | Metric tons | 52.14% |
| 2005 | 1200000 | Metric tons | 9.09% |
| 2006 | 950000 | Metric tons | -20.83% |
| 2007 | 1000000 | Metric tons | 5.26% |
| 2008 | 1100000 | Metric tons | 10.00% |
| 2009 | 1200000 | Metric tons | 9.09% |
| 2010 | 1300000 | Metric tons | 8.33% |
| 2011 | 1350000 | Metric tons | 3.85% |
| 2012 | 1700000 | Metric tons | 25.93% |
