That is an interesting question....
though I doubt you will get an answer any more accurate than if you were asking how many gents a lady sees in a day/week/month - or what her annual income was.
That isn't to say that many of us don't have alternate means of income. I am simply stating that 1) you are not taking a random sample, and 2) those ladies inclined to answer the question will be those who have a more diversivied life, thereby skewing your sample even more.
With that said, I will toss in my personal vote (which will likely be pretty close to every answer you will get).
I have several other 'jobs'. None of them nine to five, and all as busy as I would like them to be.
I do volunteer work (no, I don't get paid, but that takes up a huge chunk of my time and other resourses)
I have two degrees which I have smushed together to create a rather interesting business on a contract basis.
I write for a column in a magazine
I avidly trade in the stock market. Not a job per se, but it does take a couple hours a day of reasearch, and I can make several trades in any given day.
I'm a swimsuit and fitness model. Anywhere from 8-20 shoots per year.
So yes, in the grand scheme of things, I would say providing companionship was a very part time endeveour for me. Life is about balance, and I don't feel as though I could ever just have a 9-5.