Very Sunday, Devon and her cousins get together for brunch. This week, Devon is in charge of making fresh-squeezed orange juice. There is a proportional relationship between the number of oranges Devon squeezes, x, and the amount of juice (in ounces) she makes, y.
x (oranges) y (ounces)
2 6
3 9
4 12
6 18
What is the constant of proportionality? Write your answer as a whole number or decimal.