distribute	reads
0-500	0
500-800	20
800-1000	4
1000-1200	7
1200-1400	1
1400-1600	5
1600-1800	0
1800-2000	1
2000-2200	1
2200-2400	0
2400-2600	0
2600-2800	0
2800-3000	2
>3000	2
