title: Percentage graph from absolute values
body: <p>I have the following data:</p>
  
  <pre><code>Date    A   B   C
  2012/07 7   6   0
  2012/08 9   4   0
  2012/09 9   3   0
  2012/10 14  2   1
  2012/11 9   16  0
  2012/12 0   14  0
  2013/01 7   9   1
  2013/02 8   13  1
  2013/03 16  62  16
  2013/04 7   12  4
  2013/05 10  11  1
  2013/06 6   37  4
  </code></pre>
  
  <p>I want to make a <strong>line graph</strong> from these data, but I want it to <strong>show percentages of line total (A + B + C)</strong> instead of the absolute values. How can I do this directly, without resorting to intermediate cells where I'd insert formulas to calculate the percentages or adding a line total column?</p>
  
  <p>So the end result should look like this:</p>
  
  <p><img src="https://i.stack.imgur.com/Yz5GZ.png" alt="enter image description here"></p>
  
  <p>But I don't want to have to "manually" create cells like these:</p>
  
  <pre><code>        A   B   C
  2012/07 54% 46% 0%
  2012/08 69% 31% 0%
  2012/09 75% 25% 0%
  2012/10 82% 12% 6%
  2012/11 36% 64% 0%
  2012/12 0%  100%0%
  2013/01 41% 53% 6%
  2013/02 36% 59% 5%
  2013/03 17% 66% 17%
  2013/04 30% 52% 17%
  2013/05 45% 50% 5%
  2013/06 13% 79% 9%
  </code></pre>