How can I compute the average of each column of a Numpy array?

E.g.

array([[ 1, 2, 3, 4],

[ 5, 6, 7, 8],

[ 9, 10, 11, 12],

[13, 14, 15, 16]])

Average should be [ 7, 8, 9, 10]

E.g.

array([[ 1, 2, 3, 4],

[ 5, 6, 7, 8],

[ 9, 10, 11, 12],

[13, 14, 15, 16]])

Average should be [ 7, 8, 9, 10]