Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 782.31201171875 | Thousand metric tons | NA |
| 2004 | 1025.50305175781 | Thousand metric tons | 31.09 % |
| 2005 | 583 | Thousand metric tons | -43.15 % |
| 2006 | 250 | Thousand metric tons | -57.12 % |
| 2007 | 551 | Thousand metric tons | 120.40 % |
| 2008 | 734 | Thousand metric tons | 33.21 % |
| 2009 | 650 | Thousand metric tons | -11.44 % |
