distribute	reads
0-500	85
500-800	15
800-1000	1
1000-1200	11
1200-1400	11
1400-1600	10
1600-1800	16
1800-2000	11
2000-2200	9
2200-2400	3
2400-2600	7
2600-2800	3
2800-3000	0
>3000	1
