distribute	reads
0-500	9404
500-800	7731
800-1000	8295
1000-1200	13519
1200-1400	21318
1400-1600	29828
1600-1800	34666
1800-2000	32489
2000-2200	26123
2200-2400	20319
2400-2600	15399
2600-2800	11728
2800-3000	8940
>3000	23312
