Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 5706.7998046875 | Thousand metric tons | NA |
| 2004 | 5836 | Thousand metric tons | 2.26 % |
| 2005 | 5970 | Thousand metric tons | 2.30 % |
| 2006 | 5952 | Thousand metric tons | -0.30 % |
| 2007 | 6234 | Thousand metric tons | 4.74 % |
| 2008 | 6600 | Thousand metric tons | 5.87 % |
| 2009 | 7000 | Thousand metric tons | 6.06 % |
