distribute	reads
0-500	221522
500-800	27651
800-1000	1655
1000-1200	402
1200-1400	117
1400-1600	22
1600-1800	11
1800-2000	6
2000-2200	1
2200-2400	0
2400-2600	1
2600-2800	0
2800-3000	1
>3000	10
