distribute	reads
0-500	2833374
500-800	528875
800-1000	107242
1000-1200	54713
1200-1400	31938
1400-1600	20642
1600-1800	14571
1800-2000	10830
2000-2200	8375
2200-2400	6703
2400-2600	5531
2600-2800	4866
2800-3000	3995
>3000	49428
