distribute	reads
0-500	0
500-800	76
800-1000	22
1000-1200	19
1200-1400	18
1400-1600	9
1600-1800	14
1800-2000	3
2000-2200	5
2200-2400	8
2400-2600	5
2600-2800	4
2800-3000	2
>3000	28
