distribute	reads
0-500	868934
500-800	54262
800-1000	4516
1000-1200	954
1200-1400	244
1400-1600	63
1600-1800	19
1800-2000	6
2000-2200	3
2200-2400	5
2400-2600	1
2600-2800	1
2800-3000	2
>3000	18
