distribute	reads
0-500	1263
500-800	2578
800-1000	2292
1000-1200	2731
1200-1400	2805
1400-1600	2809
1600-1800	2379
1800-2000	2077
2000-2200	1791
2200-2400	1549
2400-2600	1440
2600-2800	1254
2800-3000	1115
>3000	12382
