A local outdoor equipment store is trying to predict the relationship between snowfall in a season and the number of snowblowers that are sold that year. The following ten years worth of data were collected:

snow (cm) number of snowblowers sold

186 19

75 15

94 13

85 9

78 8

100 17

125 19

138 16

179 22

70 13

What is the correlation coefficient? State your answer as a decimal. Be sure to use a NEGATIVE number if the data represents a negative relationship.