distribute	reads
0-500	250427
500-800	14935
800-1000	1445
1000-1200	266
1200-1400	72
1400-1600	16
1600-1800	10
1800-2000	5
2000-2200	3
2200-2400	0
2400-2600	2
2600-2800	2
2800-3000	1
>3000	1
