What's the best way to visually show social mobility over time?

So imagine you have a graph showing the distribution of wealth and you collect this data over many years giving you multiple graphs of the distribution of wealth and you know who have changed from being rich to poor and visa versa.
What’s the best way to visually show how many people have changed their income compared to how much they used to make?

So imagine we collected the data only from people making 40,000 in 1980 and we followed how much they made until the year 2000 and me made a graph in 2000 showing how much they all make now, but I want something to show this for all incomes over time.