distribute	reads
0-500	45873
500-800	88344
800-1000	53915
1000-1200	41125
1200-1400	26816
1400-1600	16503
1600-1800	9388
1800-2000	5053
2000-2200	2521
2200-2400	1283
2400-2600	563
2600-2800	184
2800-3000	69
>3000	34
