Interesting: nominally more of the bottom quintile both stay in that quintile, and make it to the top quintile, than stay in the top, and drop to the bottom.

  bottom -> bottom: 41%
  top -> top:       40%

  bottom -> top: 9%
  top -> bottom: 8%

I guess that's kind of evidence for mobility? From the shapes of the other bands, coming from money still massively biases for ending up with it, and not coming from it against.