Answer
Mean with U.S.: 2,604.28
Mean without U.S.: 2,427.71
Difference (how much the mean increases with the U.S. counted): 176.57
Work Step by Step
Sum of all countries (with U.S): 91150
# countries: 35
$ 91150 / 35 = 2604.28 $
Sum of all countries (without U.S.): 82542
# countries (without U.S.): 34
$ 82542 / 34 = 2427.71 $
$2604.28 - 2427.71 = 176.57 $