Heres some info on how much oil by weight, i haven't checked the site for accuracy or proper relevance but interesting reading anyway.
Hemp seeds typically contain 30–35% oil by weight, although some varieties contain up to 50% oil. Hemp seed oil is extremely high in essential fatty acid (EFA) content. The content of oil in hemp seed can register a slight decrease in the production losses due to drought and low levels of precipitation during the growth period. The greatest losses were is found in Diana monoecious variety (26.54-20.82%) followed by Zenit varieties (27.37-22.97%), Armanca (29.27-25.32%), Silvana (28.89-25.04%) and Denise (26.96-25.30%).