Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1689.04699707031 | Thousand metric tons | NA |
| 2004 | 2055.93994140625 | Thousand metric tons | 21.72% |
| 2005 | 2120.8779296875 | Thousand metric tons | 3.16% |
| 2006 | 2661.77001953125 | Thousand metric tons | 25.50% |
| 2007 | 2700 | Thousand metric tons | 1.44% |
| 2008 | 2779.07495117188 | Thousand metric tons | 2.93% |
| 2009 | 2483.60498046875 | Thousand metric tons | -10.63% |
| 2010 | 2607.64990234375 | Thousand metric tons | 4.99% |
| 2011 | 2542.14306640625 | Thousand metric tons | -2.51% |
| 2012 | 3592.81298828125 | Thousand metric tons | 41.33% |
| 2013 | 3590 | Thousand metric tons | -0.08% |
