distribute	reads
0-500	4789
500-800	136
800-1000	64
1000-1200	24
1200-1400	11
1400-1600	7
1600-1800	8
1800-2000	6
2000-2200	5
2200-2400	4
2400-2600	3
2600-2800	2
2800-3000	0
>3000	21
