distribute	reads
0-500	347
500-800	1712
800-1000	1946
1000-1200	1962
1200-1400	1840
1400-1600	1788
1600-1800	1754
1800-2000	1738
2000-2200	1665
2200-2400	1700
2400-2600	1562
2600-2800	1586
2800-3000	1659
>3000	38916
