distribute	reads
0-500	15
500-800	0
800-1000	1
1000-1200	0
1200-1400	2
1400-1600	3
1600-1800	2
1800-2000	6
2000-2200	5
2200-2400	1
2400-2600	6
2600-2800	4
2800-3000	7
>3000	77
