distribute	reads
0-500	174493
500-800	4625
800-1000	259
1000-1200	62
1200-1400	18
1400-1600	5
1600-1800	2
1800-2000	0
2000-2200	0
2200-2400	0
2400-2600	1
2600-2800	0
2800-3000	0
>3000	0
