Answer
The data set of United States is more variable.
Work Step by Step
Calculate the mean, standard deviation and the coefficient of variance for each data set.
United States: mean=3386.6, standard deviation=693.9, coefficient of variance $CVar1=s/X=693.9/3386.6=0.205$
World: mean=4997.8, standard deviation=803.2, coefficient of variance $CVar2=s/X=803.2/4997.8=0.161$
AS CVar1>CVar2, we conclude that the data set of United States is more variable.
