I actually published less than 5 in November. Much of the earnings were a result of already published stories prior to that month. What I have experienced is a "resurgence" of older stories. Moreover, I think if you can make your stories "evergreen" in nature (continual value that doesn't expire in terms of content) you better equip the story for earning over the long haul.
If you're starting out — I would recommend perhaps 5–10 a month (closer to 10 if you have the bandwidth). I say this considering your experience level etc (how "good" of a content writer are you? I have a handful of years experience freelancing so I believe I am equipped to churn out evergreen content).
There's a lot of nuance and I hope some of this feedback helps out.