Among the issues reported by other comments, those over index for the size of the state. Nebraska produces close to twice as much corn as Indiana for example, it’s just a much larger state.

For those looking for concrete data:

Iowa: 13.1M acres

Illinois: 11.2M acres

Nebraska: 9.95M acres

Minnesota: 8.6M acres

Indiana: 5.45M acres

Ohio: 4.75M acres

Source (switch state name at end of url for others): https://www.nass.usda.gov/Quick_Stats/Ag_Overview/stateOverv...