title: Pandas DataFrameGroupBy export to Excel
body: <p>I'm trying to export the count of grouped records to Excel.</p>
  
  <p>I have CSV file that looks like this:  </p>
  
  <pre><code>Date        Country   Sub  Source
  2014-09-11    US      1    source1
  2014-09-11    US      2    source2
  2014-09-11    UK      1    source3
  2014-09-11    US      1    source1
  2014-09-11    IN      3    source4
  </code></pre>
  
  <p>I need the grouped count of records by Country, Sub and Source.</p>
  
  <pre><code>df = pd.read_csv('log.csv',sep='\t')
  count = df.groupby(['Country','Sub','Source']).size()
  count.to_excel('report.xls', index=False)
  </code></pre>
  
  <p>But I get an error when I run it: <code>AttributeError: 'Series' object has no attribute 'to_excel'</code></p>
  
  <p>Is exporting a DataFrameGroupBy to Excel not allowed?
  Also is there a way to insert grouped records with the count info into a MySQL database?</p>