I normally read at work. So in a six hour shift I can read 200-300 pages, but that's around serving people, doing chores and such things. How much I read also depends on if I can concentrate on the book. When I get excited I tend to prolong the excitement by putting the book down and pace while thinking about what might happen. If it's too boring at a part, I put the book down and have trouble picking it back up so I might only read a few pages in an hour. So in a week I can read 2-5 books or not even finish one, and it depends on how big the books are as well.
I can read about 400 pages in 5-6 hours. ._.
Which, I suppose now, is quite slow compared to you.
That test says I read 975 words per minute and 290% faster than the national average.
I have to read 3 - 4 novels a week and class readings so I've learned to read fast. I can finish a 400 page YA book in 2 hours.
According to that Staples test, I read 194 words a minute, which is 22% slower than the national average.
I used to read a book a week, but I don't have that kind of time any more. When I do get to read, I like to take my time and enjoy the book because like someone else said before, I might miss details from rushing.