Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 93700 | Thousand metric tons | NA |
| 2004 | 99700 | Thousand metric tons | 6.40% |
| 2005 | 94900 | Thousand metric tons | -4.81% |
| 2006 | 98200 | Thousand metric tons | 3.48% |
| 2007 | 98100 | Thousand metric tons | -0.10% |
