distribute	reads
0-500	0
500-800	84
800-1000	11
1000-1200	9
1200-1400	6
1400-1600	6
1600-1800	1
1800-2000	0
2000-2200	1
2200-2400	0
2400-2600	1
2600-2800	0
2800-3000	0
>3000	2
