| year | Production | Unit of Measure | change |
| 2002 | 100 | Thousand metric tons of contained nitrogen | NA |
| 2003 | 100 | Thousand metric tons of contained nitrogen | 0.00 % |
| 2004 | 100 | Thousand metric tons of contained nitrogen | 0.00 % |
| 2005 | 100 | Thousand metric tons of contained nitrogen | 0.00 % |
| 2006 | 100 | Thousand metric tons of contained nitrogen | 0.00 % |
Source: United States Geological Survey (USGS) Minerals Resources Program