distribute	reads
0-500	322
500-800	1357
800-1000	986
1000-1200	1097
1200-1400	1347
1400-1600	1475
1600-1800	1507
1800-2000	1605
2000-2200	1628
2200-2400	1605
2400-2600	1656
2600-2800	1623
2800-3000	1535
>3000	29329
