Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 4737.10009765625 | Thousand metric tons | NA |
| 2004 | 4705.60009765625 | Thousand metric tons | -0.66% |
| 2005 | 4815.39990234375 | Thousand metric tons | 2.33% |
| 2006 | 4883.7998046875 | Thousand metric tons | 1.42% |
| 2007 | 4942.60009765625 | Thousand metric tons | 1.20% |
| 2008 | 5160 | Thousand metric tons | 4.40% |
| 2009 | 5130 | Thousand metric tons | -0.58% |
