question on crosstab usage
#### Code Sample, a copy-pastable example if possible

```python
import pandas as pd

_DEF = '../pydata-book/examples'
tips = pd.read_csv(_DEF+'/tips.csv')
party_counts = pd.crosstab(tips.day, tips.size)

print(party_counts)
#unepected result i got instead,
#col_0  1464
#day        
#Fri      19
 #Sat      87
#Sun      76
#Thur     62

```
#### Problem description

as explained in the 0.17 documentation crosstab should return a frequency for
each item with a different value

https://pandas.pydata.org/pandas-docs/version/0.17.0/generated/pandas.crosstab.html

in a more recent instead of it says that it's just a function required if you have used the values
(after testing I can assume the default is just a sum of occurrences).

https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.crosstab.html

Question:
how can I reproduce the default result provided by the old version obtaining a matrix of frequencies?

tk in advance,lp