I tend to agree that saving the data to a separate file is a better solution. However, it's not true that __END__ doesn't work with <DATA>. Either __END__ or __DATA__ may be used to signify the end of the code and the beginning of data which may be read from the special DATA filehandle.

perldata:

       The tokens __END__ and __DATA__ may be used to indicate
       the logical end of the script before the actual end of
       file.  Any following text is ignored, but may be read via
       a DATA filehandle: main::DATA for __END__, or
       PACKNAME::DATA (where PACKNAME is the current package) for
       __DATA__.
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And an example:

#!perl
while (<DATA>) {
  print;
}
__END__
Hello, world!
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produces: Hello, world!