немножко попарсил жуйк, пересёк новый, 2011, год:
juick=> SELECT date_trunc('day', at), COUNT(*) FROM threads GROUP BY date_trunc('day', at) ORDER BY date_trunc('day', at) DESC LIMIT 20;
date_trunc | count
------------------------+-------
2011-01-18 00:00:00+03 | 406
2011-01-17 00:00:00+03 | 1235
2011-01-16 00:00:00+03 | 1009
2011-01-15 00:00:00+03 | 980
2011-01-14 00:00:00+03 | 1288
2011-01-13 00:00:00+03 | 1353
2011-01-12 00:00:00+03 | 1348
2011-01-11 00:00:00+03 | 1377
2011-01-10 00:00:00+03 | 1199
2011-01-09 00:00:00+03 | 1136
2011-01-08 00:00:00+03 | 1108
2011-01-07 00:00:00+03 | 984
2011-01-06 00:00:00+03 | 1172
2011-01-05 00:00:00+03 | 1074
2011-01-04 00:00:00+03 | 961
2011-01-03 00:00:00+03 | 924
2011-01-02 00:00:00+03 | 883
2011-01-01 00:00:00+03 | 907
2010-12-31 00:00:00+03 | 1344
2010-12-30 00:00:00+03 | 1166
(20 rows)