distribute	reads
0-500	41342
500-800	31987
800-1000	19349
1000-1200	18088
1200-1400	16573
1400-1600	15650
1600-1800	14030
1800-2000	13114
2000-2200	12208
2200-2400	11074
2400-2600	10333
2600-2800	9527
2800-3000	8686
>3000	110672
