This should get you started.
https://en.wikipedia.org/wiki/European_Potato_Failure
[TABLE="class: wikitable"]
[TR]
[TH][/TH]
[TH="colspan: 4"]Potatoes[/TH]
[TH]Rye[/TH]
[TH]Wheat[/TH]
[TH]Oats[/TH]
[/TR]
[TR]
[TH][/TH]
[TH]arable land[/TH]
[TH]consumption[/TH]
[TH]1845 yield[/TH]
[TH="colspan: 4"]1846 yield[/TH]
[/TR]
[TR]
[TH][/TH]
[TH](%)[/TH]
[TH](kg/capita daily)[/TH]
[TH="colspan: 5"](% change on normal)[/TH]
[/TR]
[TR]
[TH]Belgium[/TH]
[TD]14%[/TD]
[TD]0.5/0.6 kg[/TD]
[TD]−87%[/TD]
[TD]−43%[/TD]
[TD]−50%[/TD]
[TD]−10%[/TD]
[TD]n/a[/TD]
[/TR]
[TR]
[TH]Denmark[/TH]
[TD]3%[/TD]
[TD]0.2/0.3 kg[/TD]
[TD]−50%[/TD]
[TD]−50%[/TD]
[TD]−20%[/TD]
[TD]−20%[/TD]
[TD]n/a[/TD]
[/TR]
[TR]
[TH]Sweden[/TH]
[TD]5%[/TD]
[TD]0.5/0.6 kg[/TD]
[TD]−20–25%[/TD]
[TD]−20–25%[/TD]
[TD]−10%[/TD]
[TD]−10%[/TD]
[TD]n/a[/TD]
[/TR]
[TR]
[TH]France[/TH]
[TD]App. 6%[/TD]
[TD]0.5 kg[/TD]
[TD]−20%[/TD]
[TD]−19%[/TD]
[TD]−20%[/TD]
[TD]−25%[/TD]
[TD]n/a[/TD]
[/TR]
[TR]
[TH]Württemberg[/TH]
[TD]3–8%[/TD]
[TD]n/a[/TD]
[TD]−55%[/TD]
[TD]−51%[/TD]
[TD]−15%[/TD]
[TD]−24%[/TD]
[TD]n/a[/TD]
[/TR]
[TR]
[TH]Prussia[/TH]
[TD]11%[/TD]
[TD]1.0/1.1 kg[/TD]
[TD]n/a[/TD]
[TD]−47%[/TD]
[TD]−43%[/TD]
[TD]−43%[/TD]
[TD]n/a[/TD]
[/TR]
[TR]
[TH]Netherlands[/TH]
[TD]11%[/TD]
[TD]0.7 kg[/TD]
[TD]−71%[/TD]
[TD]−56%[/TD]
[TD]−47%[/TD]
[TD]−6%[/TD]
[TD]n/a[/TD]
[/TR]
[TR]
[TH]Spain[/TH]
[TD]2%[/TD]
[TD]low[/TD]
[TD]n/a[/TD]
[TD]n/a[/TD]
[TD]n/a[/TD]
[TD]n/a[/TD]
[TD]n/a[/TD]
[/TR]
[TR]
[TH]Highlands of Scotland[/TH]
[TD]n/a[/TD]
[TD]high[/TD]
[TD]n/a[/TD]
[TD]−80%[/TD]
[TD]n/a[/TD]
[TD]n/a[/TD]
[TD]n/a[/TD]
[/TR]
[TR]
[TH]Ireland[/TH]
[TD]32%[/TD]
[TD]2.1 kg[/TD]
[TD]−30%[/TD]
[TD]−88%[/TD]
[TD]n/a[/TD]
[TD]n/a[/TD]
[TD]−33%[/TD]
[/TR]
[TR]
[TD="colspan: 8"]Source: Eric Vanhaute, et al.,
The European subsistence crisis of 1845–1850: a comparative perspective[/TD]
[/TR]
[/TABLE]