my $AVERAGE_OVER = 10; # number of periods for moving average
...
my @averages = do {
  my $sum = 0;
  my @summers = ();
  map {
    $sum += $_;
    push @summers, $_;
    $sum -= shift @summers if @summers > $AVERAGE_OVER;
    $sum / @summers;
  } @data; # THIS IS THE INPUT DATA
};