Not attainable by single stage soak-only liquid solvent based extractions.
We regularly extract over 93% of cannabinoids from the biomass into our solvent in our liquid phase extractions on the first try, and with some tuning for a given biomass type/batch/grind we have been able to consistently get over 99%.
See here for a general description of the procedure: It washes the cannabis and then it washes the cannabis some more