. . . snip . . .
shift @headings;
print join(", ", map {qq("$_")} @headings), "\n";

# Extract the data
while (<DATA>) {
    last if /-----/;
    my @fields = split /\s*%\s*/;
    shift @fields;
    for my $i (0 .. $#fields) {
        if ($fields[$i] =~ /[^-\+\.0-9]/) {
            # has non-numeric characters, so quote it
            $fields[$i] = qq("$fields[$i]");
        }
    }
    print join(", ", @fields), "\n";
}
 . . . snip . . .