Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 1739.98803710938 | Thousand metric tons | NA |
| 2003 | 1946.90002441406 | Thousand metric tons | 11.89 % |
| 2004 | 2329.4169921875 | Thousand metric tons | 19.65 % |
| 2005 | 2270 | Thousand metric tons | -2.55 % |
| 2006 | 2146 | Thousand metric tons | -5.46 % |
| 2007 | 1723 | Thousand metric tons | -19.71 % |
| 2008 | 2020 | Thousand metric tons | 17.24 % |
| 2009 | 2000 | Thousand metric tons | -0.99 % |
