Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 431.600006103516 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 403.600006103516 | Thousand metric tons of contained nitrogen | -6.49% |
| 2005 | 460 | Thousand metric tons of contained nitrogen | 13.97% |
| 2006 | 400 | Thousand metric tons of contained nitrogen | -13.04% |
| 2007 | 400 | Thousand metric tons of contained nitrogen | 0.00% |
| 2008 | 400 | Thousand metric tons of contained nitrogen | 0.00% |
| 2009 | 400 | Thousand metric tons of contained nitrogen | 0.00% |
