distribute	reads
0-500	548764
500-800	809771
800-1000	337633
1000-1200	244260
1200-1400	186097
1400-1600	146308
1600-1800	115147
1800-2000	92410
2000-2200	75254
2200-2400	61979
2400-2600	51650
2600-2800	43854
2800-3000	37553
>3000	299062
