distribute	reads
0-500	13194
500-800	5937
800-1000	4979
1000-1200	6336
1200-1400	13825
1400-1600	27989
1600-1800	47900
1800-2000	70597
2000-2200	91088
2200-2400	109131
2400-2600	119517
2600-2800	122150
2800-3000	118810
>3000	558796
