title: bar chart with Matplotlib
body: <p>Here is my data structure:</p>
  
  <pre><code>data = {'2013': {1:25,2:81,3:15}, '2014': {1:28, 2:65, 3:75}, '2015': {1:78,2:91,3:86 }}
  </code></pre>
  
  <p>My x-axis is the number <code>[1,2,3]</code></p>
  
  <p>My y-axis is the quantity of each number. For example: In 2013, <code>1</code> is x axis while its quantity is <code>25</code>. </p>
  
  <p>Print each individual graph for each year</p>
  
  <p>I would like to graph a bar chart, which uses matplotlib with legend on it.</p>