I'm pretty big on checking the validity of the data that I get as well as doing the correct kind of actions with it. Perl is naturally magnificent at doing both in one fell swoop:

#!/usr/local/bin/perl -w
use strict;

while (my $val = <DATA>) {
   chomp $val;
   print "Read: $val - ";
   # Only accept input values which consist of NNNN.NNNNN, one per lin
+e
   if ($val =~ s/^\d{2}(\d{2})\.(\d{5})$/$1$2/) {
      print "format OK, changed to $val.\n";
   }
   else {
      print "item $val not in YYYY.NNNNN format.\n";
   }

}
__DATA__
1996.40637
1996.41064
1996.41199
1996.41467
1996.41882
11996.41882
1997.418828
1998.4128
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