distribute	reads
0-500	249363
500-800	16512
800-1000	1580
1000-1200	453
1200-1400	127
1400-1600	25
1600-1800	7
1800-2000	2
2000-2200	1
2200-2400	0
2400-2600	0
2600-2800	0
2800-3000	1
>3000	3
