distribute	reads
0-500	205
500-800	180
800-1000	193
1000-1200	326
1200-1400	557
1400-1600	904
1600-1800	1214
1800-2000	1480
2000-2200	1581
2200-2400	1387
2400-2600	1207
2600-2800	924
2800-3000	769
>3000	2639
