Is this GDP measured per free person in America or does it include slaves or is it the traditional American a slave counts a 3/5 person for the purposes of gove

Is this GDP measured per free person in America or does it include slaves or is it the traditional American a slave counts a 3/5 person for the purposes of government? I recall reading somewhere James Madison bragging about his yearly investment in his slaves was $12 and his return was $250, and this is only about 10 years before the UK outlawed slavery in total across the empire.