distribute	reads
0-500	3801
500-800	5832
800-1000	2342
1000-1200	1771
1200-1400	1585
1400-1600	1264
1600-1800	1174
1800-2000	1154
2000-2200	1186
2200-2400	1144
2400-2600	1117
2600-2800	1090
2800-3000	1129
>3000	20187
