distribute	reads
0-500	332
500-800	1019
800-1000	871
1000-1200	1127
1200-1400	1401
1400-1600	1542
1600-1800	1572
1800-2000	1461
2000-2200	1551
2200-2400	1329
2400-2600	1294
2600-2800	1235
2800-3000	1196
>3000	23100
