How do I save the relative row or column frequencies after tab twoway in a matrix?

[Michael Anbar]

If I run this code:

sysuse auto, clear
tab rep78 foreign, nofreq row matcell(freqs)
matrix list freqs

it's clear that tab only saved the actual counts in each cell, not the frequencies that were calculated and displayed with the nofreq row options. How do I save these relative frequencies in a matrix? I can back them out manually, but since Stata has already calculated them, there should be a way to save them.

Also posted on Stackoverflow: http://stackoverflow.com/q/29834523/2766558

[Nick Cox]

See the Stack Overflow thread for some answers.