This is a fairly straightforward calculation.
In 1971 the 1% had 27% of the US's wealth and 8.7% of the US's income. In 2012 they had 41.8% of the wealth and 21.2% of the income. That means as the economy grew rather than sharing the growth, they kept more and more for themselvses. As a result, the 1%'s wealth has increased by 14.8% of the wealth and their income has increased by 12.6% since 1971.
What if that increase in wealth and income had gone to the 99% and economic inequality had remained flat since 1971? In 2014 the total US wealth was $84 trillion and the total income paid out was $11.1 trillion. There are also 120,780,000 households (the 99%) in the US. If we multiply 14.8% by $84 trillion and $11.1 trillion by 12.6%, and then divide by the number of households, we get amount that should have gone to each household. Thus, each household would have $102,931 more in wealth and $11,552 more in income had the 1% not been quite so greedy.
Note that this assumes an even distribution to everyone in the 99%. So in this calculation everyone, and everyone you know, gets the same increase. However, you could image other ways to distribute it.
Also, don't worry about the 1%, they would still be crazy rich.