distribute	reads
0-500	155940
500-800	3995
800-1000	501
1000-1200	223
1200-1400	100
1400-1600	50
1600-1800	36
1800-2000	17
2000-2200	15
2200-2400	11
2400-2600	5
2600-2800	5
2800-3000	2
>3000	3
