distribute	reads
0-500	14471
500-800	21888
800-1000	9365
1000-1200	6999
1200-1400	5550
1400-1600	4771
1600-1800	4197
1800-2000	3902
2000-2200	3629
2200-2400	3309
2400-2600	3227
2600-2800	3140
2800-3000	2957
>3000	45467
