distribute	reads
0-500	8785
500-800	21817
800-1000	11509
1000-1200	7993
1200-1400	5326
1400-1600	3590
1600-1800	2325
1800-2000	1606
2000-2200	1129
2200-2400	726
2400-2600	542
2600-2800	339
2800-3000	267
>3000	612
