def _get_pc_covered_str(self):
        """Returns the percent covered, as a string, without a percent sign.

        Note that "0" is only returned when the value is truly zero, and "100"
        is only returned when the value is truly 100.  Rounding can never
        result in either "0" or "100".

        """
        pc = self.pc_covered
        if 0 < pc < self._near0:
            pc = self._near0
        elif self._near100 < pc < 100:
            pc = self._near100
        else:
            pc = round(pc, self._precision)
        return "%.*f" % (self._precision, pc)