distribute	reads
0-500	0
500-800	1
800-1000	2
1000-1200	0
1200-1400	1
1400-1600	3
1600-1800	5
1800-2000	5
2000-2200	15
2200-2400	16
2400-2600	15
2600-2800	24
2800-3000	26
>3000	94
