distribute	reads
0-500	75264
500-800	89304
800-1000	26775
1000-1200	16790
1200-1400	11683
1400-1600	8164
1600-1800	6287
1800-2000	4880
2000-2200	3950
2200-2400	3296
2400-2600	2728
2600-2800	2213
2800-3000	1923
>3000	15203
