It is a common misunderstanding that the zoning classifications can be interpreted as follows...

In fact, it doesn't work that way at all. 

So, how can we understand the limits of how many unrelated people can live in a property based on the zoning of that property?

The city has all of this information neatly organized on their website here.  I have included a (somewhat blurry) screen capture below.

Of note, there can be exceptions to these generalities -- based on a special use permit for a property, or if a property use is "grandfathered in" based on that use existing since before zoning regulations limited the use.

But this is a very helpful starting point for understanding how many unrelated people can live in a property in the City based on the zoning of that property.