Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 3770000 | Metric tons | NA |
| 2004 | 4550000 | Metric tons | 20.69 % |
| 2005 | 4710000 | Metric tons | 3.52 % |
| 2006 | 4940000 | Metric tons | 4.88 % |
| 2007 | 4820000 | Metric tons | -2.43 % |
| 2008 | 4910000 | Metric tons | 1.87 % |
| 2009 | 3650000 | Metric tons | -25.66 % |
