title: Plotting average of multiple variables in time-series using ggplot
body: <p>I have a file which contains time-series data for multiple variables from a to k.</p>
  
  <p>I would like to create a graph that plots the average of the variables a to k over time and above and below that average line adds a smoothed area representing maximum and minimum variation on each day. </p>
  
  <p>So something like confidence intervals but in a smoothed version.</p>
  
  <p>Here's the dataset: 
      <a href="https://dl.dropbox.com/u/22681355/co.csv">https://dl.dropbox.com/u/22681355/co.csv</a></p>
  
  <p>and here's the code I have so far:</p>
  
  <pre><code>library(ggplot2)
  library(reshape2)
  meltdf &lt;- melt(df,id="Year")
  ggplot(meltdf,aes(x=Year,y=value,colour=variable,group=variable)) + geom_line()
  </code></pre>