Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1380.59997558594 | Thousand metric tons | NA |
| 2004 | 1457.40002441406 | Thousand metric tons | 5.56 % |
| 2005 | 1498.5 | Thousand metric tons | 2.82 % |
| 2006 | 1605 | Thousand metric tons | 7.11 % |
| 2007 | 1655 | Thousand metric tons | 3.12 % |
| 2008 | 1661.09997558594 | Thousand metric tons | 0.37 % |
| 2009 | 1535.90002441406 | Thousand metric tons | -7.54 % |
