title: How can I find the percentage of something in a column of dataframe in Python?
body: <p>I have the following dataframe</p>
  <pre><code>import pandas as pd
  
  df = pd.DataFrame({'Volcano Name': ['a', 'b', 'a', 'c', 'b', 'b', 'e', 'd', 'b', 'e', 'e'],
                     'Start Year': [1960, 1962, 1961, 1961, 1961, 1960, 1959, 1959, 1958, 1960, 1958],
                     'VEI': [0.0, 3.0,3.0,2.0, 3.0, 1.0, 1.0, 0.0, 2.0, 1.0, 2.0],
                     'Lat': [31, 31, 31, 31, 31, 31, 31, 31, 31, 31, 31]})
  </code></pre>
  <p>How can I find the percentage of each volcano by VEI? there were similar question here but couldn't figure out how to implement in mine.</p>
  <p>I guess I should start by something like</p>
  <pre><code>df.groupby('VEI').count()
  
  or
  
  df.pivot_table( index=['Volcano Name','VEI'], columns='Volcano Name')
  </code></pre>
  <p>thank you</p>