Usual weekly earnings of full-time wage and salary workers, college graduates, upper limits of quartiles and selected deciles, third quarter 1999 averages First decile $428 First quartile 606 Second quartile (median) 867 Third quartile 1238 Ninth decile 1749 Deciles divide the dataset into 10 equal-size groups and quartiles divide the dataset into 4 equal-size groups.