distribute	reads
0-500	271
500-800	788
800-1000	427
1000-1200	675
1200-1400	1078
1400-1600	1568
1600-1800	1991
1800-2000	2303
2000-2200	2467
2200-2400	2420
2400-2600	2180
2600-2800	1868
2800-3000	1561
>3000	4897
