distribute	reads
0-500	43117
500-800	53600
800-1000	15561
1000-1200	8949
1200-1400	5695
1400-1600	3814
1600-1800	2826
1800-2000	2174
2000-2200	1893
2200-2400	1472
2400-2600	1365
2600-2800	1171
2800-3000	1081
>3000	22015
