Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 311.899993896484 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 311.299987792969 | Thousand metric tons of contained nitrogen | -0.19% |
| 2005 | 329.744995117188 | Thousand metric tons of contained nitrogen | 5.93% |
| 2006 | 370.393005371094 | Thousand metric tons of contained nitrogen | 12.33% |
| 2007 | 343.785003662109 | Thousand metric tons of contained nitrogen | -7.18% |
| 2008 | 393 | Thousand metric tons of contained nitrogen | 14.32% |
| 2009 | 390 | Thousand metric tons of contained nitrogen | -0.76% |
| 2010 | 357 | Thousand metric tons of contained nitrogen | -8.46% |
| 2011 | 380 | Thousand metric tons of contained nitrogen | 6.44% |
| 2012 | 341 | Thousand metric tons of contained nitrogen | -10.26% |
