# verbose:
my @stats;

# Initialize the 12 months:
my $months = 12;
for (0..$months-1) {
  $stats[$_] = []; # empty array at first
};

my $month = 2;
my $value = 300;
push @{ $stats[ $month ] }, $value;

my $nr = 2;
print join ",", @{ $stats[ $nr ] };