This is the link which shows that employment increased to over 60% of the population from 40% in 1960.
So employment increased by 20 percentage points.
That means, if we go by that data alone, there is 50% increase in workforce, plus all the technological advancement which made workforce more productive.
Logically from this, it would have been expected that Americans become at the very least 50% to 100% richer than they were 70 years ago.
However, this isnt really the case. We have plenty of Americans who are living on the edge of poverty.
So despite massive increase in workforce both by percentage and actual number, and advancements in production, we are not really seeing average American enjoying the benefit.
One reason for this is massive increase in government budget.