distribute	reads
0-500	3913
500-800	2640
800-1000	2295
1000-1200	3395
1200-1400	4976
1400-1600	7727
1600-1800	12385
1800-2000	19318
2000-2200	28544
2200-2400	39620
2400-2600	50506
2600-2800	59011
2800-3000	64667
>3000	290034
