Not a universal rule, that will vary by region.
Then on the individual scale you can also transition near completely if you want to. I already have.
Even starting to grow some of my own food, land rental is pretty cheap for the amount I should be able to produce. Obviously focusing on somewhat higher value crops, herbs, rhubarb, kale, spring onions. Rather than potatoes. Also everything I am planning on growing long term is perennial. Just using annuals to fill gaps while propagating more of everything else.