Carolyn Dicey Jennings' research here is helpful (this is for 2011-2012 data):
Although some hirees have as many as 14 total publications and 7 top-15 publications, the median number of publications is 1 for both tenure-track and postdocs (0 for top-15 publications)The data for 2012-2013 is here.
2012-2013 tenure-track hirees had a mean 2.22 peer-reviewed publications and 0.49 peer-reviewed publications in a top-15 journal (according to the same top-15 journal list used in 2011-2012: http://the-brooks-blog.blogspot.be/2011/01/top-philosophy-journals-initial-results.html). Postdoctoral hirees had a mean 1.48 peer-reviewed publications and 0.3 peer-reviewed publications in a top-15 journal. The medians for both tenure-track and postdoctoral hirees were 1 peer-reviewed publication and 0 peer-reviewed publications in a top-15 journal. (here)The data shows the unsurprising fact that the top departments place a lot of their grads. What it shows in terms of publications is that the numbers are all over the place. People were hired with 0 pubs and with 14 pubs. Pubs in top journals were rare.
Putting on my speculator's hat: the further out you are from your PhD, the worse it will look if you are not publishing. One explanation for this is that you might look like a bad bet for earning tenure if you've been fallow, research-wise, for a few years--worse than a fresh PhD with no pubs. Bottom line: you should be publishing. (Anecdotally, I know of two resignations this year in a single department at my university--both people were in year 5, coming up for tenure, with 0 publications. No books, no papers. You can't get tenure with no publications, unless you're at a school where they absolutely don't care about publishing. [If there are such places.]) This gets me wondering about the issue of PhD "staleness." Is staleness really just a function of your years post-degree, or your level of post-degree productivity, or both? That is, do you still go stale if you publish regularly?
Philosophy departments have their own standards for how much/often you have to be publishing to earn tenure. But you don't have to already be qualified for tenure to get a tenure track job. If there are standards for getting a TT job, the Jennings data shows that the number of publications is not a deciding factor (thus people with 0 pubs get hired, all things considered). The Chronicle has this interesting story (here and here) on two hires (in English), and what it takes to stand out in a crowded field. (Spoiler alert: there are lots of applicants with lots of pubs.)
So, how much will it help you in the job search if you are publishing a lot? And how much is enough?