Suppose a restaurant manager collects the customer surveys that were submitted during the previous month. One of the questions asks for a rating from 0 to 10 about the quality of the visit. The average overall rating is about 8.2. But when these ratings are grouped by the waiter who served the customer, the separate waiter-group averages range from about 7.4 to about 9.2. If the total sum of squares equals 289 and the within-group sum of squares equals 151 (when grouped by waiter), what is the coefficient of determination, to the nearest percentage, of the separate waiter-group averages as a summary of the customer ratings