use strict;
use warnings;
my $count = 0;
my $sum = 0;
my $previous_hour = -1;
while (<DATA>) {
    chomp;
    next if /^itemid/;
    my @F = split;
    my @J = split(/\:/,$F[2]);
    my $hour = $J[0];
    if ($hour != $previous_hour && $count) {
        print $previous_hour, " ", $sum / $count, "\n";
        $sum = 0;
        $count = 0;
    }
    $sum += $F[-1];
    $count++;
    $previous_hour = $hour;
}