For an employer sponsored visa, I think they should be included in the count for that question provided you want them to be included in your visa.
I'm currently filling in my 47SP for a partner visa and there is a similar question. I am not including my husband as he is an Australian citizen so he is not going to be included on my visa. Therefore, my answer is 1 (just me!). If I had a child and they needed to be on the visa then I would answer 2 (my child and I).
On that basis, if you partner doesn't have their own visa and needs to be included on yours then I think you should include them in that answer.
I'm no expert though - just my view from filling in the partner visa forms