title: Get values from matplotlib AxesSubplot
body: <p>I'd like to get values from <code>matplotlib.axes.AxesSubplot</code> which is returned from <a href="http://pandas.pydata.org/pandas-docs/version/0.17.0/generated/pandas.Series.hist.html" rel="noreferrer">pandas.Series.hist</a> method.
  Is there any method to do so? I couldn't find the attribute in the list.</p>
  
  <pre><code>import pandas as pd
  import matplotlib.pyplot as plt
  
  serie = pd.Series([0.0,950.0,-70.0,812.0,0.0,-90.0,0.0,0.0,-90.0,0.0,-64.0,208.0,0.0,-90.0,0.0,-80.0,0.0,0.0,-80.0,-48.0,840.0,-100.0,190.0,130.0,-100.0,-100.0,0.0,-50.0,0.0,-100.0,-100.0,0.0,-90.0,0.0,-90.0,-90.0,63.0,-90.0,0.0,0.0,-90.0,-80.0,0.0,])
  hist = serie.hist()
  # I want to get values of hist variable.
  </code></pre>
  
  <p>I know I can get histogram values with <code>np.histogram</code>, but I want to use pandas hist method.</p>