distribute	reads
0-500	349
500-800	7
800-1000	2
1000-1200	1
1200-1400	2
1400-1600	2
1600-1800	1
1800-2000	6
2000-2200	2
2200-2400	2
2400-2600	11
2600-2800	5
2800-3000	4
>3000	40
