title: MultiIndex Group By in Pandas Data Frame
body: <p>I have a data set that contains countries and statistics on economic indicators by year, organized like so: </p>
  
  <pre><code>Country  Metric           2011   2012   2013  2014
    USA     GDP               7      4     0      2
    USA     Pop.              2      3     0      3
    GB      GDP               8      7     0      7
    GB      Pop.              2      6     0      0
    FR      GDP               5      0     0      1
    FR      Pop.              1      1     0      5
  </code></pre>
  
  <p>How can I use MultiIndex in pandas to create a data frame that only shows GDP by Year for each country?</p>
  
  <p>I tried: </p>
  
  <pre><code>df = data.groupby(['Country', 'Metric'])
  </code></pre>
  
  <p>but it didn't work properly.</p>