Here is the same chart showing an absolute value instead of percentage change. Not quite as steep of a dive - https://fred.stlouisfed.org/graph/fredgraph.png?g=17uvX - in fact, nothing that could be considered a "dive" by any reasonable person.
It's much more eye opening as well, productivity per hour of labour has doubled from the baseline right before 1990, salaries have definitely not increased at the same rate.
