Don't be so hard on yourself Lilli. That is still a heck of a lot of words for one month. I wouldn't think "professional" writers pop out 50k in 30 days on a regular basis anyway. Every year you keep doing more and more, and you beat your all time high. Heck, that's a lot to be proud of. Shows growth as a writer I think.
I'm really struggling with this myself this year, its only the third time I've done it. My 09 story was great, this one just sucks.
I tried last year but only got as far as 19k I think.
I "failed" five years out of seven, if it's any consolation. It was only this year that I felt organized enough to pull it off without breaking a sweat -- there's been a lot of learning going on.
And Lilli, I still want to read what you've written. Where's my email?
As far as professional authors are concerned, at the beginning of our first NaNo, my daughter and I had the pleasure of meeting Tamora Pierce, and she said that she does about 60k in two months, or about 30k a month.
And average of 1000 words per day, in other words, well under NaNo rates.
Some professionals write more, some less in an average month. It depends on what they're writing, how fast they write, how well the particular book is going, and the alignment of the stars, at least as far as I can figure out.
The important thing I've found out though, is whether they write a hundred words a day or a thousand is that they write every day.
So that's my goal: A minimum of 100 words each and every day until my current NaNo and my 2008 NaNo (which I abandoned in December after my first win) are finished. Then I'll take a break from writing, and start revising the heck out of both books.