As a young girl, Brenna enjoyed watching her father make things in his woodworking shop. Now that she's grown up, Brenna builds wooden furniture for a living. Her most popular product is a cedar porch swing. There is a proportional relationship between the time (in days) Brenna spends making porch swings, x, and the number of swings she builds, y.
x (days) y (swings)
16 12
28 21
36 27
44 33
What is the constant of proportionality? Write your answer as a whole number or decimal.
swings per day