Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 321.200012207031 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 320 | Thousand metric tons of contained nitrogen | -0.37 % |
| 2005 | 320 | Thousand metric tons of contained nitrogen | 0.00 % |
| 2006 | 309 | Thousand metric tons of contained nitrogen | -3.44 % |
| 2007 | 310 | Thousand metric tons of contained nitrogen | 0.32 % |
| 2008 | 310 | Thousand metric tons of contained nitrogen | 0.00 % |
| 2009 | 310 | Thousand metric tons of contained nitrogen | 0.00 % |
