Rate  c_pp  c_xs  cbxs  perl
c_pp 3.03e-02/s    --  -97%  -97%  -98%
c_xs     1.07/s 3434%    --   -1%  -34%
cbxs     1.08/s 3453%    1%    --  -33%
perl     1.61/s 5229%   51%   50%    --

##</code><code>##

""|201407|"Jul|2014"|" "|"BLANK"|" "|" "|" "|"CAN01"|" "|" "|" "|" "|"09/09/9999 00:00:00"...
              ^

##</code><code>##

$ cat test.pl
use strict;
use warnings;

use Text::CSV_XS;

my $csv = Text::CSV_XS->new ({ binary => 1, sep_char => "|", auto_diag => 1 });

open my $fh, "<", "Proj20101111.csv" or die $!;

my @hdr = map { lc } @{$csv->getline ($fh)};
my %rec;
$csv->bind_columns (\@rec{@hdr});
my %count;
while ($csv->getline ($fh)) {
    $count{$rec{client_id}}++;
    }
printf "%-8s %7d\n", $_, $count{$_} for sort keys %count;
$ perl test.pl
104167      1001
116571      4004
BLANK      24024