Are 95% and 99% difficult to parse? Plus, does "I've seen it in Perl" nullify the "an idiom you haven't seen" for the rest of millions of programmers that don'

Are 95% and 99% difficult to parse? Plus, does "I've seen it in Perl" nullify the "an idiom you haven't seen" for the rest of millions of programmers that don't use Perl, or J, or ...?