Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 55.2999992370605 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 47.5 | Thousand metric tons of contained nitrogen | -14.10 % |
| 2005 | 30 | Thousand metric tons of contained nitrogen | -36.84 % |
| 2006 | 10 | Thousand metric tons of contained nitrogen | -66.67 % |
| 2007 | 35 | Thousand metric tons of contained nitrogen | 250.00 % |
| 2008 | 25 | Thousand metric tons of contained nitrogen | -28.57 % |
| 2009 | 20 | Thousand metric tons of contained nitrogen | -20.00 % |
