c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = 'A man, a plan, a canal: Panama!';
 ;;
 my %freq;
 ++$freq{ substr $s, $_, 1 } for 0 .. length($s) - 1;
 ;;
 printf qq{'$_' (0x%02x) == $freq{$_} (%6.3f%%) \n},
   ord, $freq{$_} / length($s) * 100
   for sort { ord($a) <=> ord($b) } keys %freq;
"
' ' (0x20) == 6 (19.355%)
'!' (0x21) == 1 ( 3.226%)
',' (0x2c) == 2 ( 6.452%)
':' (0x3a) == 1 ( 3.226%)
'A' (0x41) == 1 ( 3.226%)
'P' (0x50) == 1 ( 3.226%)
'a' (0x61) == 9 (29.032%)
'c' (0x63) == 1 ( 3.226%)
'l' (0x6c) == 2 ( 6.452%)
'm' (0x6d) == 2 ( 6.452%)
'n' (0x6e) == 4 (12.903%)
'p' (0x70) == 1 ( 3.226%)