title: How to plot stacked proportional graph?
body: <p>I have a data frame:</p>
  
  <pre><code>x &lt;- data.frame(id=letters[1:3],val0=1:3,val1=4:6,val2=7:9)
    id val0 val1 val2
  1  a    1    4    7
  2  b    2    5    8
  3  c    3    6    9
  </code></pre>
  
  <p>I want to plot a stacked bar plot that shows the percentage of each columns. So, each bar represents one row and and each bar is of length but of three different colors each color representing percentage of val0, val1 and val2. </p>
  
  <p>I tried looking for it, I am getting only ways to plot stacked graph but not stacked proportional graph.</p>
  
  <p>Thanks.</p>