my $district;
my $ID;
my $index_num = 0; # initialize counter

print qq(<TABLE><TR><TD>\n);
while (($district,$ID) = $sth->fetchrow_array) {
  print qq(<a href="$ID">$district</a> <br>\n);
  if (++$index_num == 200) {
    # end of index list, end TD and reset counter
    print qq(</TD><TD>\n);
    $index_num = 0;
  }   
}
print qq(</TD></TR></TABLE>\n);