distribute	reads
0-500	0
500-800	103
800-1000	27
1000-1200	18
1200-1400	12
1400-1600	7
1600-1800	4
1800-2000	1
2000-2200	7
2200-2400	6
2400-2600	3
2600-2800	8
2800-3000	3
>3000	61
