[General] meaning of a sentence from Do Androids Dream of Electric Sheep?

[KuaiLe]

Dear all,

I'm reading Do Androids Dream of Electric Sheep? by Philip K. Dick. The opening chapter of it mentions about "Empty apartments" and it goes:

"Empty apartments," Rick said. Sometimes he heard them at night when he was supposed to be asleep. And yet, for this day and age a one-half occupied conapt building rated high in the scheme of population density; out in what had been before the war the suburbs, one could find buildings entirely empty . . . or so he had heard. He had let the information remain secondhand; like most people he did not care to experience it directly.

I'm confused about the meaning and sentence structure of the sentence in red. Does "a one-half occupied conapt building rated high in the scheme of population density" mean that "a one-half occupied apartment is considered very populated"? If not, what does it mean?

And I'm totally lost about "out in what had been before the war the suburbs, one could find buildings entirely empty". The structure doesn't seem grammatical to me. I just don't understand what it's talking about. Can anybody explain the sentence for me?

 

[SoothingDave]

A "conapt" is apparently this author's term for "condominum apartment." This is not a real word in English that I am aware of.

Compared to the areas where many of the buildings are empty, the half-filled conapt is high density populated. It's relative.

Before the war, the areas he is talking about were suburbs. Out in them, one could find buildings completely empty. Out in the suburbs. Out in (what had been before the war) the suburbs