In 『よつばと!』, やつば says 「ここ家がいっぱいある」 to which her father replies 「そうだろう」.

What's the difference between そうです and そうでしょう? I know when we use そうです but I can't figure out the other. I know ましょう is used to suggest stuff, but I don't know how it fits with そうでしょう.