title: ggplot2 - shade area between two vertical lines
body: <p>I am using <code>ggplot2</code> to create some fairly simple scatter plots. I currently have two simple vertical lines using:</p>
  
  <pre><code>... + geom_vline(xintercept=159684.186,linetype="dotted",size=0.6)+
  geom_vline(xintercept=159683.438,linetype="dotted",size=0.6)+ ...
  </code></pre>
  
  <p>Can anyone tell me how to shade the area between these two lines from the top of the Y axis to the X axis?</p>