Not pertinent to your problem (and I note that you no longer initialise the hashes anyway) but you could save yourself some typing by using map and sprintf to do the work. Your

my %G01totals = (
    '01' => 0, '02' => 0, '03' => 0, '04' => 0, '05' => 0, '06' => 0, 
+'07' => 0,
    '08' => 0, '09' => 0, '10' => 0, '11' => 0, '12' => 0, '13' => 0, 
+'14' => 0,
    '15' => 0, '16' => 0, '17' => 0, '18' => 0, '19' => 0, '20' => 0, 
+'21' => 0,
);
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could be written

my %G01totals = map { sprintf( q{%02d}, $_ ) => 0 } 1 .. 21;
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I hope this might be useful in the future.