#!/usr/bin/perl

use strict;
use warnings;

use Data::Dumper;

my %stats;

while (<DATA>) {
  next unless /(\d+)\s+(\d+)/;
  $stats{$2} += $1;
}

print Dumper \%stats;

_ _DATA_ _                   
183                        
5      1                   
78    2                    
73    3                    
20    4                    
7      5                   
                                      
 285    
  9      1
 79     2
 128   3
 63     4
  5      5
   1      6