Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 461.799987792969 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 424 | Thousand metric tons of contained nitrogen | -8.19% |
| 2005 | 430 | Thousand metric tons of contained nitrogen | 1.42% |
| 2006 | 453.299987792969 | Thousand metric tons of contained nitrogen | 5.42% |
| 2007 | 935.900024414063 | Thousand metric tons of contained nitrogen | 106.46% |
| 2008 | 759 | Thousand metric tons of contained nitrogen | -18.90% |
| 2009 | 472.399993896484 | Thousand metric tons of contained nitrogen | -37.76% |
| 2010 | 434.100006103516 | Thousand metric tons of contained nitrogen | -8.11% |
| 2011 | 869.5 | Thousand metric tons of contained nitrogen | 100.30% |
| 2012 | 918.400024414063 | Thousand metric tons of contained nitrogen | 5.62% |
