distribute	reads
0-500	261886
500-800	32855
800-1000	3299
1000-1200	769
1200-1400	203
1400-1600	57
1600-1800	16
1800-2000	2
2000-2200	1
2200-2400	0
2400-2600	0
2600-2800	1
2800-3000	0
>3000	0
