Percent repeat counter starting at 1

[David Sumbler]

By default the percent repeat counter does not put a "1" over the bar
which is to be repeated; it starts with a "2" over the first actual
repetition.

This is what is normally required, but for clarity in one particular
instance I would like the repeat counter to put a "1" over the bar
which is going to be repeated.

Is there a simple way of telling the repeat counter to do this?  If
not, it is not too difficult to fake it, of course.  But if the
facility to change the counter's behaviour is already available in
Lilypond, then that will no doubt be the simplest solution for me to
use.

David