use Text::CSV_XS;

my $csv = Text::CSV_XS->new ({ binary => 1, allow_whitespace => 1, auto_diag => 1 });
my $fs = -s $ARGV[0] or die "Empty input file";
open my $fh, "<", $ARGV[0];
while (my $row = $csv->getline ($fh)) {
    print int (100 * tell ($fh) / $fs), "%%\r";
    my $sstation = $row->[5];
    ...