5 weeks: 3 responses.
6 weeks: 5 responses.
7 weeks: 9 responses.
Is it just that things move slowly, or:
a) there isn't enough interest even to send a "No."
b) there's some interest, so they're thinking about it, and might get back to me eventually.
c) Killer Yapp ate the query letter, fuggedibout it.
Answering queries is a low priority. However, that's not the most helpful answer since you knew that already.
Just for added perspective, here's a list of what's in my incoming stack, today, after getting rid of all the easy "nos" over the weekend.
Category: query, novel, first page ok, set aside to read
19 letters dated June 29, June 27, June 24, June 11, two undated, June 10, another undated, June 12, June 13, June 13, June 11, May 27, May 30, June 2, June 2, May 22, May 31, May 23
Category: Query that needs more than form rejection cause I went to the school where the guy teaches-May 29
Query that says it has an SASE but I can't find: May 31
Query from previously published author: June 9, June 12
Query from someone at writing conference: June 14
Revisions from query dated April 25
Query sent on referral by author I respect: May 30
Query dated March 21, partial received thereafter
Query dated March 1, partial received thereafter
Partial sent May 31
8 others sent December-June
Unsolicited novel, previously represented, no SASE-waiting for form rejection letter
From this I think you can conclude that when I don't respond right away it's cause there's a problem, or I'm considering it.
Remember too, your query is the only thing you're thinking about. Here, if you survive the initial weed out from 100/week, you're still on my stack today that has 26 queries and 11 partials. And I'd rather be answering Miss Snark's email than actually yanno...working.