This is the important part. With increased efficiency and by shifting more pastoral land to agriculture we could easily boost this to 100%.
At the end of the day the temperate crops such as wheat, potatoes and apples are vastly more important than non-temperate produce such as bananas and rice.

What I’am interested in is how much a country can produce itself, what it can produce should be maximised. Of course we can still keep importing food and warm climate produce, but we should aim close to 100% cool climate, staple crop self-sufficiency, a sort of strategic food reserve if you like.
We can always import cool climate crops too, since subsisting on our own crops would be quite a limiting existence, but we do need to be 100% self-sufficient (or close) at a staples and decent diet level in case the worst case happens.

Thanks for the figures, I’ve been wondering for a long time how self-sufficient in cool-weather crops we are.