How much biofuel is there in regular diesel?

Both automotive diesel and off-road diesel follow the requirements of EN590 (in Europe), which allows up to 7% FAME (Fatty Acid Methyl Ester), which in Norway is often RME (Rapeseed Methyl Ester). Off-road diesel has historically not had this blended in, even though the EN590 standard allows it.

FAME must not be confused with HVO/GTL/BTL, which are other synthetic variants or products from renewable sources. These are permitted as blends in automotive and off-road diesel as long as the product itself meets the requirements of EN590

For further details on Norwegian requirements, we recommend Drivkraft Norge's publication: Norwegian industry standard for fuels and heating products (link)