So was the effect. The change in 1971 was an inflection point in the first derivative. In point of fact, ~1971 seems to be almost exactly when this started.

So was the effect. The change in 1971 was an inflection point in the first derivative. In point of fact, ~1971 seems to be almost exactly when this started. For reference, the term "Silicon Valley" was first used in print in 1971!