If you averaged over both the life of the individual and over the individuals in humanity, I would think it came out negative, but not too negative. Reason, "into each life some rain must fall" is a saying that we don't reject indignantly, rather we shake our heads in mournful recognition of the truth. And we are among the richest and well endowed folks on the face of the earth. what must they feel in rural China or Africa?
Here are some statistics. Note that these are only the top 50, and most of Africa is missing, so the result is probably fairly low though still above 0.
Edit: Maybe the average (rating of 52 from -100 to 100) is for all countries, I don't know.