distribute	reads
0-500	2344
500-800	889
800-1000	581
1000-1200	643
1200-1400	756
1400-1600	950
1600-1800	1293
1800-2000	1741
2000-2200	2358
2200-2400	2985
2400-2600	3599
2600-2800	4251
2800-3000	4433
>3000	35718
