distribute	reads
0-500	15
500-800	16
800-1000	10
1000-1200	10
1200-1400	18
1400-1600	8
1600-1800	18
1800-2000	23
2000-2200	21
2200-2400	19
2400-2600	36
2600-2800	50
2800-3000	69
>3000	2879
