distribute	reads
0-500	159003
500-800	23507
800-1000	1627
1000-1200	391
1200-1400	91
1400-1600	29
1600-1800	23
1800-2000	8
2000-2200	5
2200-2400	0
2400-2600	0
2600-2800	1
2800-3000	0
>3000	1
