distribute	reads
0-500	35772
500-800	54807
800-1000	24326
1000-1200	19756
1200-1400	16225
1400-1600	13836
1600-1800	11583
1800-2000	9851
2000-2200	8278
2200-2400	6981
2400-2600	5671
2600-2800	4813
2800-3000	3966
>3000	19085
