title: Plotting multiple time series on the same plot using ggplot()
body: <p>I am fairly new to R and am attempting to plot two time series lines simultaneously (using different colors, of course) making use of ggplot2. </p>
  
  <p>I have 2 data frames. the first one has 'Percent change for X' and 'Date' columns.  The second one has 'Percent change for Y' and 'Date' columns as well, i.e., both have a 'Date' column with the same values whereas the 'Percent Change' columns have different values.  </p>
  
  <p>I would like to plot the 'Percent Change' columns against 'Date' (common to both) using ggplot2 on a single plot. </p>
  
  <p>The examples that I found online made use of the same data frame with different variables to achieve this, I have not been able to find anything that makes use of 2 data frames to get to the plot. I do not want to bind the two data frames together, I want to keep them separate. Here is the code that I am using:</p>
  
  <pre><code>ggplot(jobsAFAM, aes(x=jobsAFAM$data_date, y=jobsAFAM$Percent.Change)) + geom_line() +
    xlab("") + ylab("")
  </code></pre>
  
  <p>But this code produces only one line and I would like to add another line on top of it.
  Any help would be much appreciated.
  TIA.</p>