Annual high temperatures in a certain location have been tracked for several years. Let XX represent the year and YY the high temperature. Based on the data shown below, calculate the correlation coefficient (to three decimal places) between XX and YY.

x y

5 37.22

6 34.23

7 34.84

8 31.25

9 25.96

10 23.37

11 20.58

12 19.69

13 16.2

Answer: r = ________________________ (to three decimal places)