distribute	reads
0-500	846960
500-800	1127408
800-1000	391398
1000-1200	248107
1200-1400	157205
1400-1600	101402
1600-1800	67283
1800-2000	46859
2000-2200	33419
2200-2400	23871
2400-2600	17322
2600-2800	12246
2800-3000	8858
>3000	89275
