distribute	reads
0-500	87996
500-800	18057
800-1000	5852
1000-1200	3797
1200-1400	2616
1400-1600	2064
1600-1800	1516
1800-2000	1204
2000-2200	1053
2200-2400	943
2400-2600	748
2600-2800	665
2800-3000	591
>3000	11086
