Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 8450 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 8990 | Thousand metric tons of contained nitrogen | 6.39% |
| 2005 | 8338 | Thousand metric tons of contained nitrogen | -7.25% |
| 2006 | 8190 | Thousand metric tons of contained nitrogen | -1.78% |
| 2007 | 8538 | Thousand metric tons of contained nitrogen | 4.25% |
| 2008 | 7870 | Thousand metric tons of contained nitrogen | -7.82% |
| 2009 | 7700 | Thousand metric tons of contained nitrogen | -2.16% |
| 2010 | 8290 | Thousand metric tons of contained nitrogen | 7.66% |
| 2011 | 9350 | Thousand metric tons of contained nitrogen | 12.79% |
| 2012 | 8730 | Thousand metric tons of contained nitrogen | -6.63% |
