distribute	reads
0-500	401
500-800	1356
800-1000	1126
1000-1200	1410
1200-1400	1612
1400-1600	1677
1600-1800	1711
1800-2000	1688
2000-2200	1689
2200-2400	1601
2400-2600	1572
2600-2800	1480
2800-3000	1361
>3000	16457
