distribute	reads
0-500	15542
500-800	9447
800-1000	4505
1000-1200	3701
1200-1400	2970
1400-1600	2536
1600-1800	2231
1800-2000	1899
2000-2200	1593
2200-2400	1340
2400-2600	1213
2600-2800	1007
2800-3000	848
>3000	7903
