my @ary = qw ( a a a a a b b b c c c c c c d d d d );

# use a hash to count occurrences
my %pop;
$pop{$_}++ for @ary;

# sort hash on values, store sorted keys in array
my @pop_sort = sort { $pop{$b} <=> $pop{$a} } keys %pop;

# now print most popular
print "Most popular $pop_sort[0]\n";
print "Least popular $pop_sort[-1]\n";

# show hash
print "Key  Count\n";
for my $key (@pop_sort) {
    print "$key => $pop{$key}\n";
}