Something like:

use YAML;
my %count_per_100k;
while (<DATA>) {
    my ($text, $count) = split;
    next unless $text =~ /gene/;
    $count_per_100k{int($count / 100_000)}++;
}
print Dump \%count_per_100k;

__DATA__
...
[download]

Output:

---
0: 14
1: 18
2: 1
[download]

At least, I think that's your question. Perhaps you want to do something different.