distribute	reads
0-500	418
500-800	1
800-1000	2
1000-1200	3
1200-1400	2
1400-1600	2
1600-1800	7
1800-2000	11
2000-2200	16
2200-2400	12
2400-2600	17
2600-2800	12
2800-3000	20
>3000	128
