Use of で when describing survey results (or answers)

Question

Could someone please explain the use of で (in bold) below? The line is taken from the article: 男の子の将来の夢は「学者」　女の子は「食べ物屋さん」 and describes the results of a survey.

女の子で１番多かったのは、２１年続けて「食べ物屋さん」で、１１．３％でした。２番目は「看護師さん」で９．５％、３番目は「保育園や幼稚園の先生」で６．９％でした。

I'm confident about what is meant (since context makes it so clear) but if I were to have constructed it myself, I never would have used で. I'd have probably done something like:
「食べ物屋さん」と答えた子が１１．３％でした
which could easily be unintelligible gibberish and would appreciate a correction is needed.

Also, I'm having a hard time finding exactly what a 食べ物屋さん is. Is this a person who prepares food at a restaurant, is it a waitress, is it just a generic term for anyone who works at a restaurant, or is it something else entirely?

Answer 1

In response to your comment, Aで、Bでした" doesn't mean A is B. I'm assuming this is sentence is describing a survey.

女の子で１番多かったのは、２１年続けて「食べ物屋さん」で、１１．３％でした。２番目は「看護師さん」で９．５％、３番目は「保育園や幼稚園の先生」で６．９％でした。

"Among girls the most frequent (answer/finding), for 21 years in a row, was waitress and was 11.3% (of the total). The second (most frequent) was nurse and was 9.5%...

So で simply means "...is X and..." or "...was X and..." just like it normally does.

By the way, I'm not sure about my translation of 食べ物屋さん. Please correct me if I got it wrong.

Answer 2

In your example, で is short for でして. This is the form of です when used to combine sentences. Instead of 「１８歳です。札幌出身です。」you would say 「１８歳で、札幌出身です。」. So, to keep from having to constantly close each sentence with です you can combine multiple sentences using this word. This is the same as using the ～て form of verbs when adding new information afterwards.

食べ物屋さん is an eatery or 'dining establishment', or in this case the proprietor of or a worker in one. Exact position is not specified.