Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1789.5 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1675.19995117188 | Thousand metric tons of contained nitrogen | -6.39 % |
| 2005 | 1640 | Thousand metric tons of contained nitrogen | -2.10 % |
| 2006 | 1800 | Thousand metric tons of contained nitrogen | 9.76 % |
| 2007 | 1750 | Thousand metric tons of contained nitrogen | -2.78 % |
| 2008 | 1750 | Thousand metric tons of contained nitrogen | 0.00 % |
| 2009 | 2000 | Thousand metric tons of contained nitrogen | 14.29 % |
