List::UtilsBy 

use List::UtilsBy       qw( count_by rev_nsort_by );
use List::Util          qw( pairs );
use Proc::ProcessTable  qw();

printf("%-10s => %4u\n", $_->key, $_->value)
    foreach rev_nsort_by { $_->value }
        pairs count_by { scalar getpwuid($_->uid) }
            @{ Proc::ProcessTable->new->table };