distribute	reads
0-500	100147
500-800	11519
800-1000	1047
1000-1200	335
1200-1400	90
1400-1600	38
1600-1800	12
1800-2000	4
2000-2200	2
2200-2400	1
2400-2600	0
2600-2800	1
2800-3000	1
>3000	6
