I can speak to those statistics.
I'm a numbers person, and that number comes from the February 2009 labour force survey. I took a sample of all women who are currently employed part-time, and 9.3% of them said they were working part-time because of business conditions and they couldn't find full-time work, and they had looked. In comparison to that, 38% of women working part-time are working part-time because they're caring for their own children.