Ik that no one would like to help me with this but my friend is not feeling well today. hes out with a cold today so can yall make sure to sub to his YT, 999 splxsh tysm

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.