In this code, I would not blindly assume the last character is a period:

 chop $fields[9];  # Remove the period after the last digit
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It's better to use a regex to remove it:

 $fields[9] =~ s{\.$}{}; # Remove any trailing period
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Then again, this shouldn't be necessary since you are using $fields[9] as a number. For instance, the strings "3.14" and "3.14." will evaluate to the same number.