TypeError: 'int' object is not iterable // numpy

TypeError: 'int' object is not iterable // numpy

Here is my function:
import numpy as np
def calc_mean():
return np.loadtxt('GOOG.csv', skiprows=1, usecols=(5)).mean(axis=0)
Here is my GOOG.csv:
Date Open High Low Close Volume Adj Close # <--
column that I need
2013-09-27 874.82 877.52 871.31 876.39 1258800 876.39
2013-09-26 878.3 882.75 875 878.17 1259900 878.17
2013-09-25 886.55 886.55 875.6 877.23 1649000 877.23
2013-09-24 886.5 890.1 881.4 886.84 1467000 886.84
2013-09-23 896.15 901.59 885.2 886.5 1777400 886.5
2013-09-20 898.39 904.13 895.62 903.11 4345300 903.11
2013-09-19 905.99 905.99 895.4 898.39 1597900 898.39
2013-09-18 886.35 903.97 883.07 903.32 1934700 903.32
2013-09-17 887.41 888.39 881 886.11 1259400 886.11
2013-09-16 896.2 897 884.87 887.76 1336500 887.76
When I run it, i have the following error:
Traceback (most recent call last):
File "/home/misha/Documents/finance/finance.py", line 164, in <module>
security_mean(file_list)
File "/home/misha/Documents/finance/finance.py", line 125, in security_mean
return np.loadtxt('GOOG.csv', skiprows=1, usecols=(5)).mean(axis=0)
File "/usr/lib/python2.7/site-packages/numpy/lib/npyio.py", line 703, in
loadtxt
usecols = list(usecols)
TypeError: 'int' object is not iterable
How can I fix that?
Thanks.
NOTE: all data in GOOG.csv are strings