[s-cars] '94 S4 rear brake pad life?

[alan page]

I changed the rear pads about 12 months ago (20K miles) and the right
one is scraping and will soon be damaging the rotor.

Any ideas on how I could go through a set of factory pads on the rear
in 20K miles? I usually go through two sets of front pads before the
rears need changing.

Thanks,
Alan
Sandy Hook, CT USA
'94 S4
'90 80q