title: How to display the order of number of elements in pandas dataframe
body: <p>I am trying to handle the following dataframe</p>
  <pre><code>import pandas as pd
  import io
  
  csv_data = '''
  ID,age,Year
  100,75,2020
  100,76,2021
  200,64,2020
  200,65,2021
  200,66,2022
  300,69,2020
  300,70,2021
  300,71,2022
  300,72,2023
  '''
  df = pd.read_csv(io.StringIO(csv_data))
  df = df.set_index(['ID', 'age'])
  df
           Year
  ID  age 
  100 75  2020
      76  2021
  200 64  2020
      65  2021
      66  2022
  300 69  2020
      70  2021
      71  2022
      72  2023
  </code></pre>
  <p>The <strong>ID</strong> in this data frame represents the <strong>same person</strong>, and <strong>Year</strong> means the year of the visit.</p>
  <p>This will be multi-indexed based on <strong>ID</strong> and <strong>age</strong>. At this point, is it possible to display from the <strong>ID</strong> with more <strong>age</strong> elements?</p>
  <p>The ideal display is shown below.</p>
  <pre><code>        Year
  ID  age 
  300 69  2020
      70  2021
      71  2022
      72  2023
  200 64  2020
      65  2021
      66  2022
  100 75  2020
      76  2021
  </code></pre>