I learned that in 1968 when I was a part of an IQ study as a records gatherer. If my memory serves me correctly, I believe the lowest was around 55.
And if whites are subhuman, then why are most of the important inventions and technological advances credited to whites?
I would say a large part of it is culture which rewards individuality, uniqueness, innovation and perpetually striving for something better so you can make a buck and live a satisfying life. In one word, capitalism. Most of man's inventions have come since the industrial revolution - capitalism.