distribute	reads
0-500	445944
500-800	35973
800-1000	1964
1000-1200	390
1200-1400	81
1400-1600	19
1600-1800	5
1800-2000	4
2000-2200	0
2200-2400	1
2400-2600	0
2600-2800	0
2800-3000	0
>3000	10
