title: How to use ggplot to group and show top X categories?
body: <p>I am trying to use use ggplot to plot production data by company and use the color of the point to designate year.  The follwoing chart shows a example based on sample data:
  <img src="https://i.stack.imgur.com/QuYbG.png" alt="enter image description here"></p>
  
  <p>However, often times my real data has 50-60 different comapnies wich makes the Company names on the Y axis to be tiglhtly grouped and not very asteticly pleaseing.  </p>
  
  <p>What is th easiest way to show data for only the top 5 companies information (ranked by 2011 quanties) and then show the rest aggregated and shown as "Other"?</p>
  
  <p>Below is some sample data and the code I have used to create the sample chart:</p>
  
  <pre><code># create some sample data
  c=c("AAA","BBB","CCC","DDD","EEE","FFF","GGG","HHH","III","JJJ")
  
  q=c(1,2,3,4,5,6,7,8,9,10)
  y=c(2010)
  df1=data.frame(Company=c, Quantity=q, Year=y)
  
  q=c(3,4,7,8,5,14,7,13,2,1)
  y=c(2011)
  df2=data.frame(Company=c, Quantity=q, Year=y)
  
  df=rbind(df1, df2)
  
  # create plot
  p=ggplot(data=df,aes(Quantity,Company))+
    geom_point(aes(color=factor(Year)),size=4)
  p
  </code></pre>
  
  <p>I started down the path of a brute force approach but thought there is probably a simple and elegent way to do this that I should learn.  Any assistance would be greatly appreciated.</p>