title: Google Chart - two date series on the same chart
body: <p>I have data about earnings occurred on some dates:</p>
  
  <pre><code>['2013-02-13',100],['2013-03-20',200],['2013-04-11',160]
  </code></pre>
  
  <p>and data about costs occurred on some other dates:</p>
  
  <pre><code>['2013-02-22',60],['2013-03-04',90],['2013-03-25',110]
  </code></pre>
  
  <p>So X-axis is continuous one (date), and Y-axis represents earning/cost values (number). I'd like to represent these two date-value series on the same chart. They share the same timeline but events occurred on different dates?</p>
  
  <p>Is this possible?</p>