Shoe survey results
City Comfort Design Color
A 3 2 4
B 7 4 8
C 5 5 9
D 10 5 8

Hip Hop Shoe Company wants to gauge opinions of a new shoe design. They send out a total of 100 pairs of shoes divided equally between four different cities, but because of cost constraints they can only interview a total of 40 people. They randomly choose 10 people from each city to interview. The table shows how many people from each city rated the shoe "positive" in each of three categories.

Using the sample results estimate the proportion of the entire population that would find the shoe comfortable.