import pandas as pn  
import numpy as np
import csv 
df = pn.read_csv('zamowienia.csv',sep=';',quotechar=';',index_col=None)
df['Data zamowienia'] = pn.to_datetime(df['Data zamowienia'], format='%Y-%m-%d')
t = df.loc[(df['Data zamowienia'] >= '2004-01-01')& (df['Data zamowienia'] < '2004-12-31')]
p=t.Utarg
y=p.mean()
print(y)