distribute	reads
0-500	941
500-800	977
800-1000	1058
1000-1200	2012
1200-1400	3598
1400-1600	5789
1600-1800	8770
1800-2000	11939
2000-2200	14493
2200-2400	16104
2400-2600	16818
2600-2800	16072
2800-3000	14823
>3000	71659
