How to plot data after groupby
<p>I have a data frame similar to this</p>

<pre><code>import pandas as pd
df = pd.DataFrame([['1','3','1','2','3','1','2','2','1','1'], ['ONE','TWO','ONE','ONE','ONE','TWO','ONE','TWO','ONE','THREE']]).T
df.columns = [['age','data']]
print(df)   #printing dataframe.
</code></pre>

<p>I performed the groupby function on it to get the required output.</p>

<pre><code>df['COUNTER'] =1       #initially, set that counter to 1.
group_data = df.groupby(['age','data'])['COUNTER'].sum() #sum function
print(group_data)
</code></pre>

<p>now i want to plot the out using matplot lib. Please help me with it.. I am not able to figure how to start and what to do. 
I want to plot using the counter value and something similar to bar graph</p>