What's the exact format of the data in this field? What spaces, labels, return characters are present in it?
I have created a temporary file that picked off the Right most 3 words, (zip, state, & City. I then peeled the three pieces off into their own fields. What's left in the Address field would be the street number & name if I could only trim, or delete away what I don't need in there anymre.
In your screen shot, I see a comma after the street number/name. Is that in every field. If so, there's your delimitter, you can return everything to the left of the position of that comma.
If not, then you have a problem as some cities have two word names--which messes up any effort to isolate addresses strictly by counting words.