title: ggplot - label as calculated increase (%)
body: <p>I have developed a ggplot graph but now I am trying to add calculated label which shows increase in % year-on-year?</p>
  
  <p>My data frame is very simple (result of aggregate from the main dataset)</p>
  
  <pre><code>'data.frame':   4 obs. of  3 variables:
   $ Year    : int  2011 2012 2013 2014
   $ TotalPay: num  71744 74113 77611 75466
  </code></pre>
  
  <p>I have a code for my graph:</p>
  
  <pre><code>library(ggplot2)
  ggplot(d1, aes(x=Year, y=TotalPay)) + geom_bar(stat="identity") + 
  labs(x="Year", y="Average Total Pay ($)")
  </code></pre>
  
  <p>and now trying to use stat_bin for lables? The calculation is Actual Year - Previous Year * 100%. I have this but not sure how to fill percent ()</p>
  
  <pre><code>stat_bin(aes (labels = paste("Total Pay" = ,scales::percent(())), vjust = 1, geom = "TexT")
  </code></pre>