Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 798.799987792969 | Thousand metric tons | NA |
| 2004 | 861.799987792969 | Thousand metric tons | 7.89 % |
| 2005 | 942.400024414063 | Thousand metric tons | 9.35 % |
| 2006 | 1105.09997558594 | Thousand metric tons | 17.26 % |
| 2007 | 1221.80004882813 | Thousand metric tons | 10.56 % |
| 2008 | 1307.5 | Thousand metric tons | 7.01 % |
| 2009 | 1400 | Thousand metric tons | 7.07 % |
