Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1906.30004882813 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1984.43395996094 | Thousand metric tons of contained nitrogen | 4.10 % |
| 2005 | 2079.94189453125 | Thousand metric tons of contained nitrogen | 4.81 % |
| 2006 | 2007 | Thousand metric tons of contained nitrogen | -3.51 % |
| 2007 | 1995 | Thousand metric tons of contained nitrogen | -0.60 % |
| 2008 | 1995 | Thousand metric tons of contained nitrogen | 0.00 % |
| 2009 | 1990 | Thousand metric tons of contained nitrogen | -0.25 % |
