I'm a reasonably fast typer and can write around 800-1000 words per hour if I sit down to focus on writing (obviously, that's a lot lower than my typing speed, but I spend about 2/3 of the time thinking and 1/3 writing in little spurts. It takes me about 20 minutes to outline one page worth of notes, from which I generally get anything from 5,000-8,000 words of written narrative. This means that, if I write/outline 2 hr/day 6 days/week, I can get about 10-12,000 words written per week. These 10-12k words are obviously a draft, but they're a decent draft because I've learned how to outline effectively for my writing style (that is, I skip over the parts I'm good at filling in on the fly and add deets at the parts where I struggle). Sometimes I take a few days off and write a lot less in a week, or in two weeks... and sometimes I go crazy with a new idea and have an 20,000 word weekend. It all amounts to about 10-12k/week.
There is nothing laudable, though, about writing lots and lots. Me writing 11,000 words of story per week is no more laudable than my playing 4 games of golf per week or practicing piano for 12 hours a week. The point is:
A) To enjoy it, if that's what you enjoy doing.
B) To get good at it by critically examining what you've done right or wrong and to focus at those weak points.
True, many famous and revered authors only write... whatever 500, 1000, 1200 words per day. But you have to read, write, and rewrite a hell of a lot to get good at the craft. Sometimes, that means writing 500 words but being super critical and super analytical-nitpicky about it. Sometimes, that means writing 2000 words and being moderately critical and analytical about it. This is an art form, and your development and expression as an artist has to be whatever works for you. If your goal is more output, there are ways to do it (just freakin' write, quality be damned), but the cornerstone to good writing isn't lots of words. It's making writing and constructive self-critique into a habit that you can do automatically.