About how many hours/week do most (non-PhD) programmers at google work
on average? Citing sources is good but not necessary.

Hello,

I asked a Google programmer your question, and unfortiunately they are
not permitted to release that type of information. As they stated:

"We have very important confidentiality clauses at Google so I can't 
really give you any kind of information about the internal policies or
practices of Google employees."