title: How to calculate the percentage of the sum value of the column?
body: <p>I have a pandas dataframe which looks like this:</p>
  
  <pre><code>Country  Sold
   Japan   3432
   Japan   4364
   Korea   2231
   India   1130
   India   2342
    USA    4333
    USA    2356
    USA    3423
  </code></pre>
  
  <p>I have use the code below and get the sum of the "sold" column</p>
  
  <pre><code>df1= df.groupby(df['Country'])
  df2 = df1.sum()
  </code></pre>
  
  <p>I want to ask how to calculate the percentage of the sum of "sold" column. </p>