use List::Util qw< min max >;
my @array = ( -150, -5, 50, 0, 7, 0, 2 ,4, 3, 8, -1 );
my $min = min(@array);
my $max = max(@array);
my @final_array = map 100*($_-$min)/($max-$min), @array;
for( 0..$#array ) {
    printf "%5.1f%% %5d\n", $final_array[$_], $array[$_];
}
__END__
  0.0%  -150
 72.5%    -5
100.0%    50
 75.0%     0
 78.5%     7
 75.0%     0
 76.0%     2
 77.0%     4
 76.5%     3
 79.0%     8
 74.5%    -1