distribute	reads
0-500	124036
500-800	6475
800-1000	330
1000-1200	73
1200-1400	20
1400-1600	15
1600-1800	4
1800-2000	7
2000-2200	2
2200-2400	4
2400-2600	1
2600-2800	5
2800-3000	2
>3000	20
