I can figure the first part out but am struggling to understand how to work part B.

I need help with my homework. I can figure the first part out but am struggling to understand how to work part B. The life spans of three randomly selected tires are 28,700 miles, 33,300 miles and 31,000 miles. Using the empirical rule, find the percentile that corresponds to each life span. Life span for 28,700 is in _ percentile, Life span of 33,300 is in _ percentile and life span of 31,000 is in _ percentile.