You could enter the data directly into a hash, below is an example which seem to match the approach you have been trying.

use strict;

my %calhash;

while (<OUTFILE>) {  # Should be <INFILE> ??
    chomp;
    my ($value, $key) = split(/;/, $_);
    $calhash{$key} = $value;
}
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Of course this requires that you are guaranteed that there is only one semicolon in each line. Otherwise you will have to use a regexp.